Transparent Carburetor (Extended Cut With My Dad Darryl) - Smarter Every Day

hey it's me destin welcome back to smarter everyday two this is the second channel on the main channel i did a video about how carburetors work by making a see-through carburetor but on this channel i want to string that out a little bit because the stuff that i did with my dad was just so cool i want to remember it i want it to exist on the internet and it helped me gain a good understanding of how carburetors work so my childhood as you can imagine was normal in the fact that i was just a little redneck kid running around alabama here but a little different in that my dad was an auto worker who was really good with mechanical stuff and i could go up to him and ask him any kind of question and we would just go down the rabbit hole well i went to visit my dad one day and he was working on his tiller and i decided you know i'm a mechanical engineer i'm supposed to know how carburetors work i should be able just to jump in and help dad but i've got time what if i just ask him how carburetors work because i have a book knowledge of carburetors and dad has a dirty fingernails knowledge of carburetors two very different things so i just suspended everything i know and i just asked him how everything worked and he walked me through every part of a carburetor so the first part of this video is just that conversation and i hope it helps you understand how they work or at least the assembly of a carburetor the operation of a carburetor comes in the second part of the video where we made a see-through carburetor and dad and i interact with it with a high-speed camera and we learn how these things work it's really fun so anyway that's what this video is we learned about the assembly and operation of carburetors and i hope at the end of this video you are no longer intimidated by small engines or carburetors like you could go clean a carburetor on a small engine this afternoon if you take the time to watch this so yeah that's it i want to say thank you to all the patrons that support smartereveryday on patreon.com smartereveryday that's huge that lets me make content i want to make without worrying about algorithms or anything like that i'm grateful for your support so thank you so much all right let's go learn about carburetors from dad yeah teach me taking the bowl out so we took the old one off right here so this is the bowl bowl you see that that's the main jet carburetor see the holes in the side yes it sucks gas up through there so it's gas in the side so that you're adjusting we're doing some gas because that's the bowl right yeah this is full of gas all right look bowl you got gasoline in there uh-huh float uh-huh where's the needle the needle is right in here see the needle going up and down right there yes sir when when your gas gums up and everything that sticks so the float so a carburetor has to have gravity to work it has to have gravity to work these and it has to have ideally you have an engine that's pointed upright yeah has to sit like that or you'll run out of fuel and the engine doesn't get any fuel okay so let me get this straight so fuel comes in right here yes hold it still so i can video here so fuel comes in right here yes it goes over and then you got two valves right here you got a valve on the back side that's the choke and you got a valve over here that's the throttle right yes that's the throttle right there you can see that okay that left more air in okay so so i'm letting more oxygen in on on on the choke choke you're running open right there choking you're running clean if i want to run more rich i close that off and that that prevents oxygen from coming in on this side right and so then the gas is coming in here it's going down into the bowl yes what what forces the pressure out what forces the gas back out through the needle the suction from the cylinder okay the suction the intake when the cylinder goes down it's a vacuum it sucks air through here and when it sucks air through here this being in the bottom of the bowl is saturated with gas that suction pulls gas in the sides right here and goes up oh so this is a pass-through this is a valve a restriction yeah yeah okay and gasoline comes up through here okay because of the suction oh so it enters the bowl so this hose right here gasoline liquid liquid form goes through the center of this hole it goes down to the boat yeah and this center holds the bowl on but when you suck right here a small amount of gasoline throw those through a little bitty or hold it let me see those little bitty orifices uh-huh and when your gasoline stops up or you get any dirt in there that's what stops up that's why you got to filter your gas line right okay right okay so the bowl is now full bowl is full when the bowl is full the float comes up the needle closes the let's see that really so when the bowl is full the float comes up and closes the the fuel so like a toilet so you want the mixture between oxygen and gasoline in the bowl to be about right you want to be liquid in here okay not full though you want some air in there too right no no no air in here nothing but liquid okay air is going to come through this way through the choke through the air filter okay and going to be sucked out okay all right the little squirt of gasoline comes up through the center of that yes they're like the main jet yes sir all right but listen to this okay can you hear that yes sir that's cutting off the flow of gasoline gasoline yeah so you got gasoline always submerging this okay when you pull on the starter rope it sucks air in here the air blowing by there pulls the vacuum sucks gasoline up here and it atomizes when the air meets the little bitty stream of gasoline uh so it's the uh where's the gasoline come up right there i don't know see right in the middle i see two holes so one of them is gas going into the bowl uh yeah no gas going into the bowl is the needle right here let me pull this needle and seed out hold on is the gas coming into the bowl from the needle or is gas coming into the bowl through that bolt hole from the needle got it it's a valve it's a valve so this right here this this hole right here this is not this is not it coming into the bowl this is it going out of the bowl right that's the main jet going you see where i hit my finger with a hammer have you ever have you ever seen a double like that no okay okay all right the gasoline goes up through here out of that main jet and goes into i think it's called a venturi okay and it's bigger on one side than it is the other side yep is it is it a hard edge or is it a look at it no it's not hard you polish it in a car or something you polish that intake got it so that orifice it's it's a rocket nozzle is what that is that's exactly what it is okay it pulls air in and accelerates when it goes through that restriction when it accelerates it's atomized as the liquid meets the airstream and the atomized air are vaporized that's right vaporized yeah wrong word goes into the cylinder the valve closes in the cylinder your compression stroke comes up compresses the gasoline your spark plug fires pushes it back down when it pushes back down inertia it makes it go down below top dead center or pushes down in the compression stroke and uh sucks squeezing stroke power stroke power stroke that's power stroke and a four-cycle engine it'll go over one time and suck in the next time compress and power stroke again got it suck squeeze bang blow and that's a briggs that's a briggs and stratton um carburetor right there right so what's bad with this carburetor why are we replacing the needle and seat the needle and seat got gummed up and is it is it brass uh no i think it's stainless it looks like stainless so do we have some like some galvanic action going on or something yeah crud uh gasoline you know chemically decomposes yeah especially it's got ethanol in it turns into slack i've heard that uh it does it turns into a shellac smelling like thing but the ethanol really is not a problem ethanol you don't hear people you don't see people sitting on side road anymore because it's got water in their gasoline because ethanol makes the water mix with the gas really it does i've never heard anybody tell me what's good about ethanol what's good about ethanol is the water mixes with the gasoline and a little bit of water in your fuel system doesn't kill your engine because oh because gasoline and water different specific gravity they don't mix they don't mix but when you've got ethanol in there it makes it more homogeneous it does oh i didn't know that okay so can i teach you how this works now yeah based on what you just taught me okay okay so we need gasoline and we need air and we need them at the right mixture in inside our engine so the first thing is how to bring air into the system and that's the choke right here which well that that restricts the air flow that restricts the air flow yeah so that's running wide open that's that's a a lean mixture right and that's a rich mixture right so when i start an engine and i'm having trouble i want to run a rich mixture okay so that's how it cranked the engine and then i'd run wide open after that okay so after it warms up a little bit after it warms up okay so i'm bringing i'm bringing air into the engine there um let's just start with a vacuum on this side so a vacuum on on this side the engine side of the carburetor is doing all the work all right your finger right there the vacuum will pull this open the vacuum will pull the throttle open yep really it's balanced like that yeah okay so the vacuum will pull the throttle open and then that makes a vacuum down there in the bottom and it pulls liquid gasoline up out of the bowl out of the bowl through that little screw over there yep okay yep through that little screw from the bottom you got a pothole right there and a smaller hole going in both sides here so when the gasoline flows in there it's already turbulent got it turbulent so it's mixing so so this is the bowl so when the bowl which is gravity fed uh well hold on the mixture is controlled by gravity as the float comes up it's it it closes off that needle that needle right it's really hard to see on this camera that needle right there so as i as i move it you can see right there okay so let me get a pair of needle nose and i'll pull the needle out all right i got something on my hip if it wasn't bent the needle would just slide out do it it should just slide out but i bent it first time i took it apart because it was all gummed up how many carburetors have you worked on in your life too many too many i i'm a child of injection uh that's a float that's the needle that's the needle can you put it back in my hand so i can focus on it okay oh it's like a two stage huh it says how much do you want and it's got a cylinder there and at one point it goes and that that's a strange here you hold the carburetor it's a strange triangular shape interesting if you could see down in there all that is is a hold of steel so i can focus plastic uh-huh and it just seats in there just like every other valve you use in plumbing right you just sits in there you tap it in with a pin punch okay so we've got um so now the float the float allows well no the needle allows fuel to go into the bowl right and then the bowl um is pressurized or not pressurized it's actually under negative pressure because of the vacuum right and then you suck the the gasoline up through the hole that little bolt that's in the bottom yeah in your hand there yeah it so so the gas goes back through there it pops up into the venturi and the flow of the venturi yes is what actually makes the uh the vaporization happen so how how do you flood an engine you flood an engine by being too rich too rich for one thing uh and the bowl gets full if you're oh wait if the if the fuel gets over the float uh yeah that that's true if fuel gets over the float it'll it'll flow around everything but when you flood an engine you're too rich and you get out there and you saturate your spark plug and your spark plug cannot fire okay so that's downstream of the carburetor okay got it got it give it too much gasoline you just soak everything down but if gasoline sits in the bowl gasoline sits in the bottom of this bowl for two years oh yeah that's what happened to this so you got to get in there and you got to clean that out yep carburetor choke cleaner okay quickly dissolves gum and varnish hey did you you didn't buy that at uh at the the parts store that i did did you all right i did what do you mean when we were in isolation yeah no i had that here awesome i feel like i understand how carburetors work still got the needle yes sir here's the way you reassemble watch the needle hooked right in there this instruction is going poorly it is see the needle hanging yes i see it let me get the bubble all right so you do a carburetor upside down is how you do it uh-huh slide the needle in there where the seat is uh-huh you get the pin which you lose usually you lose it or you bend it this should just slide in very easily i think you gotta align that hole you do all right and once it's in there the bowl right there keeps it from coming out but i'm gonna have to squeeze it a little bit because i've been at the first time it come out because it was all shellac if i were to take that new carburetor apart that pen would just fall out got it okay because you don't want any restriction on that you want the bowl to float freely when i turn it over for the float to float freely yeah you want that and that's what i didn't have because the shellac and gum was just cementing the uh the needle in the needle in position so it's a function of the resistance of the needle and that hinge yes okay and then you put it in there's a o-ring around here and o-ring around here and if it were transparent you could look at it the gasoline would be about halfway to three-quarters of the way up right here because of the setting of the float on the old tractors on the old john deere tractors it was a glass bowl literally a glass bowl that you could look at yes that would get broke every once in a while i've never seen one broke it was thick glass but when it would gum up and everything you could definitely see it so that was a way you could troubleshoot instantly oh yeah you know if you had fuel know if you had fuel come down to the carburetor so if you want to and the carburetor for john deere didn't look much different than that right there if you want to fix a carburetor you walk up the first thing you do is take the bowl off uh take this out yeah and see if you're that this is a main jet right there yes it stopped up and you run a wire you get a piece of wire from your loaf of bread that's twisted take the plastic off of it and run it through there like that and run it through there like that and make sure you can blow through it or because you might have trash in there yes or you take that carburetor cleaner right there and blow it on top and they actually have a countersink on some of these that you can put that little stem in so you can pressurize the whole system yes you can interesting and once you uh drop that needle and seat out you take this and spray up around the thing you don't want to put anything in there if you put a nick in that seat at all you'll never show still off the gas that's what's wrong with this one which seat the seat between the needle and the seat yeah the seat yes it's polished yeah got it and that's carburetor that is a carburetor okay so dad's teaching me about carburetors we've spent the time to make these 3d carburetors that we can see through right right so i want to look at this first right so this is the carburetor that's very similar to the one the tiller that you showed me how to build rebuild right okay so here is a tiller so my thought is i want to run that tiller with a carburetor that we can see what's going on right yep and so this is the evolution of design we started with the venturi here then uh went along the way we knew we needed a bowl we need the venturi all the way up all these iterations and we ended up here this carburetor has a venturi on top it's got the bowl down in the bottom as the bowl um has the float in it here this needle is way back in there it's kind of hard to see as the float comes up it'll stop up that needle there and we also have the choke and the throttle and can you explain what the choke and the throttle are for just so i make sure i understand well the choke when you want to be richer to start it you can choke a little bit restrict the amount of air going in it makes it more rich and the throttle is how much vapor actually gets to the combustion chamber but the choke once you start it with a rich mixture you open the choke up allow more air to go in and the throttle gives it more or less have to be careful now break that yeah more or less fuel air mixture going into the combustion chamber ideally you could use the choke and the throttle to get your stoichiometry right and you can have an ideal mixture right so what i want to do is i'm going to see that and the idea of seeing that is using a high-speed camera here to basically look inside that venturi to see if we can see a little puff of cloud downstream it should be downstream of the venturi right yes yes downstream of the throat i should say yes it should be vaporizing or here on the suction side have lots of air coming in here a little bit of fuel liquid fuel coming in here and a fuel air mixture going out there but it would only vaporize like when you have negative pressure on the engine side right so on the what do you call the stroke intake stroke intake contact so on intake we should see a cloud on the exhaust stroke we should not see a cloud is that true uh on the intake your intake valve is open it lets it suck going that way you get down to bottom dead center and you come back up during a compression stroke that vaporized air uh fuel mixture uh combusts pushes it down when the the next when the piston comes back up the exhaust valve opens the exhaust goes out exhaust valve closes intake valve opens and you suck in the next charge of air fuel mixture what cars did you have that had a carburetor 69 road runner do a line holley i hated that thing because you had to fix it i couldn't get it to run right sure couldn't it'd run good at high speed but wouldn't run it idle get it to run it out and it was bad at high speed you know could not get the mixture right it's more of an art than a science uh i bought a carter to go on it which is i think what chrysler used at the time i put it on didn't touch anything everything run right really yeah so the engineers at the plant oh they knew what they were doing they tuned it yeah and amateur uh young men who thought they could improve things screwed everything up were you about to say rednecks there's rednecks everywhere all right let's see what we can do let's see if we can see what about the fuel source here yep we got to do that too you want to see the fuel running in there and watch a bowl come up oh that's a great idea ready okay i'm gonna open the fuel here goes and it'll just fill up it should i don't know why didn't you know that's what no one did not know that was what was gonna happen well yeah i mean it's obvious now that you do it ah that's what the fire extinguisher is for so as the gas is flowing in like we've already the see-through carburetor concept has already yeah taught me things so like as soon as you that's why ethanol is such a big deal because it sits in the bowl like that and turns to slack right it gets gummy well just gasoline does this chemically decomposes over time yeah it will evaporate it will vaporize and and what's left what you're seeing now is the the float is down letting the gasoline flow your tank has to be vented also so air can go in here and gasoline can run down here when that float comes up it will cut off the flow and it will have a happy level there about time for the boat the float to start moving up when you run out of fuel this bowl right here yeah thump that right there let's see let me make sure okay i think yeah our float came up no i would have expected the float to be half submerged yeah it's it's a pretty complicated uh but now we have liquid fuel down here and we have a straw sticking down in there which is the main jet is what that is on some carburetors you control the throttle by putting a tapered needle in and out of that main jet uh-huh to control the flow to control the flow but on this one you control it here gotcha so given this right now we should be able to crank this up and she should run right i think so all right so how about now backfiring is an issue right it is an issue and how about getting this ready to go yeah because we spilled some gasoline a few minutes ago so so if if a backfire happens if i understand correctly fire's going to come backwards back into the carburetor and we did not pressure test this carburetor right so this this could explode and all this gas could be on fire and go around us right hopefully not okay so we will have that okay our fuel is about half the bowl full that's pretty good design so far okay i don't know if this uh the diameter of this incoming fuel flow would be enough to run it at high rpm for very long i i don't i don't think we this this bad boy is ready to go okay okay all right so um i say we goggle up okay there you go what do you think yep i'm a little mad at myself for not realizing that the bowl would just flow up as soon as we opened the valve right i don't i'm just i should have known that well that's the purpose of needling seat in the boat yeah i know the flow yeah okay so a lot of those floats are made out of brass yeah like a brass foil kind of like aluminum foil and they'd get a pin hole in them get fuel on the inside and they wouldn't float and you never could cut off the flow of fuel so is it better to they wouldn't float they would just oh i see they're plastic now and they even make foam ones now that makes but they usually closed cell foam would be important wouldn't it yeah yeah but they used to use brass all right this is cool okay now if it starts we're gonna have to control the speed of the engine here uh-huh and we are in a choke position right there well we need a way to turn off that uh fuel if we need to that clamp right there so we can do that well if you do that it's gonna burn all the fuel in the bowl yes which is fine so choking it's going to be or just stuff putting your thumb over that would stop it it stopped the air that's true yeah you feel good about this yeah i think the gas that we spilled is now evaporated and gone away okay as a matter of fact open the door just a little bit let whatever vapors here on the floor go out okay well we may be able to i just want the lighting yeah that looks good lighting wise that looks fine how about we run it like this okay okay are you excited about this yeah i think we're about mid throttle i don't think the throttle means anything we had to guess at everything right okay so that means nothing okay so the original throttle is here so if i want slow or fast what's happening over here you have a connecting rod here that slowed we go down i catch cut off that so if i go boom that's that's slow yeah if you pull that way if i pull it pulls that in and that would control the throttle that would open it up so there'd be a control linkage there yes okay so i think the first time we filled it up the float was dragging on the side of the bowl or the needle was not properly seated in that little tube going to the seat so we have too much fuel in it right now but let's just burn it off if we can see what happens i'm ready yeah you ready your choke is on all the way right now so we're gonna open that up right very little okay we want a rich mixture to start it okay ready yeah i don't think we have ignition so you need fuel fire hold on let me pull this over all right give it a shot oh i saw some vapor did you feel the intake stroke yeah we're gonna see it oh it's running okay i'll trigger we can kill it kill it yeah you can see the vapor in the intake can you yeah you can did you see it no what do you mean you didn't see that i was looking for fire did you not no you could see vapor i could see something right in here right yeah yeah okay did you catch it with the i don't know i think i hit the buttons listen okay yeah so we got a wide angle shot that was such a large amount of work for such a little payoff okay all right here let's go look at it all right all right so i don't know how this works you see our fuel levels above our float yeah why is that bad uh just say it you're getting too much fuel too much fuel yeah too much fuel of course it's not running out the top you notice the way it was running rich and i opened the choke up a little bit no it did not yeah it was running rich it's butter and splash but so i opened the choke up so it'd lean out the mixture and it started running smoother like it like it was actually supposed to be used well yeah that's what it's supposed to work all right that's really really cool all right so here let's let's look at this i could see it right up in here a little bit oh you're i got it with your you were adjusting it yeah oh yeah you see vapor don't you [Music] oh look at that is it yep you can see the vortex behind the throttle do you see that you can oh it is it is okay so that's intake yep look you can actually see it squirting okay so that's too much okay we got so many things wrong there's so many things wrong with this right what well first of all look at our bowl yes the gas is over overfilled yeah over over the float we've submerged the float is that what it means for it to be flooded no no flooding is when you have so much fuel in here that in the throttle body yeah in the intake this is intake that's what they were polishing we were talking about earlier about polishing so you're polishing downstream of the venturi so that everything will flow quickly and smoothly into the combustion chamber okay sounds good that's where they polished okay but yeah you can see air air fuel mixture going in combustion chamber and so that's exit exhaust stroke this is intake fire intake is when it's sucking in right intake yeah fire you can take valve closes exhaust stroke yes another intake right okay so you're actually adjusting the choke right now yes so because it was running rough open it up a little bit and it'll it'll start increasing so this is so fast we can't see what's happening you can actually see the fuel jumping up in there yeah well we could crank it and let it run and then i'm listening uh take another high-speed shot with it running in a stable condition you know so can you run two cylinders off of one carburetor oh yeah yeah or three or four yeah really yeah okay the the carburetor all it does is mix fuel and air and yeah you got one carburetor runs eight cylinders are you serious yeah so it's running really really fast yeah it's atomizing air each cylinder sucks in what it can use burns it sucks in only what it can use volumetrically right now my motorcycle has a carburetor for each cylinder and you have to balance those because if you have one one that's hitting harder because it's getting a different rod it won't run smooth at all so the advantage of running multiple cylinders off of one carburetor is you get the same stoichiometric mixture throughout yes but it has to have a higher flow rate i would say so so the orifice diameter is a function of flow rate at certain pressures or other way around yeah yeah i know what you're saying but you have to have enough airflow and fuel flow to feed all eight cylinders got it okay look at this one so oh so you have two high-speed cameras running yes okay so this is this one provides context and that one zoom in yeah oh yeah you can see it right there can't you yeah [Music] yeah on the one center you see suction section section but if you had eight cylinders it would be almost continuous flow probably [Music] you could actually see the dwell time between cylinders i like how everything's shaking yeah and you can see the crank turning that's cool everything's in time that's where i was adjusting maybe i shouldn't have done that on frame but who cares it's awesome we're running a see-through carburetor engine i was trying to make it smooth out well that's the that's why you're here because you intuitively knew i mean yeah i know how to do it on a lawn mower because i'm sitting in the seat and i know how to operate it but you know how you have a different understanding of or i guess i should say relationship with carburetors than i have because this is how you grew up you didn't just turn the creek key and go yeah i could hear the mixture being rich yeah yeah the orlean you could tell yeah more of a cough that was lean yeah that's awesome i'm gonna go get trent real quick okay i want him to see this so here's the question if if i have a cylinder it is a set volume on the the intake stroke i know i'm gonna have a set amount of air or volume mixture whatever come into that thing right i understand what the choke does it provides head pressure on the back side it's like how hard i have to pull all that stuff what i don't understand is the throttle side because all that volume is going to come out one way or the other so either going to come from the inside on the inlet or it's going to come from the bowl right and that's i understand how it controls my mixture on the choke side i don't understand what the throttle is doing it allows more to get to the combustion chamber but the same amount it's going to go into the cylinder every time no no it i it should depend on your atmospheric pressure but if you choke it off you're only going to get a half charge if you let it flow you'll get more air fuel mixture in there which will give you a stronger stroke okay got it so that so the the the cylinder is a vacuum yes it's a negative pressure yes and if i don't allow more to flow in right uh you don't have to so when i cut off the valve you know when i'm at maximum stroke on my intake when i cut off the valve i've got a set amount of pressure there and then i compress it and then boom and so i just didn't pull my syringe hard enough well your syringe is going to move no matter what but if you close that off the engine is going to die because it gets no fuel air okay if you open it up you get more and it accelerates and runs faster normally you cut your engine off by closing your throttle but we don't have a throttle that we can close all the way because we didn't have the butterfly set correctly on our tolerances well we got good enough to run all right and we can open it up so you want to run it yeah let's just run it okay i want to see the vortex shedding off the back side of the throttle let's see if we can let's see if we can see if we can make it let's just get it run first okay ready no not one second at first i didn't think we had uh ignition you got to have four things for it to work you have to have fuel air ignition and compression or compression and ignition fuel air fire compression right okay maybe not in that order but we're going to start the engine by running rich and we got enough airflow we know it'll run i'm going to run rich by restricting the flow of air lets the the vacuum increase up more as it warms up i'm going to open up the air let more air in and i'm going to throw control the throttle right here all right and then i'm going to get that on high speed as you do that where's that fire extinguisher yeah just in case with the garage door open all the vapor goes out it hugs the ground here we go it's got a response time yeah so there's a uh there's no spring to hold the choke so there's a delay but you could see you could see there what i wanted to say but but when you throw i didn't trigger i forgot to trigger the high-speed camera well that's okay you can see it on that camera yeah but when you throttle up it takes a second for the engine to spin up because of inertia in the engine it's got to suck it in there yeah right oh okay that's what this is right here on this throttle right here the holes there's little bitty holes on the side and that's a transition so like as you're closing down or opening the throttle it needs that extra fuel to come over so that helps you transition we don't have that no we don't have a that's why we don't have an idle setting do we yeah that's why this right here that's why this this one right here has this hole up in the top right of the throttle yeah see that yeah that's to help it says it's for a transition like in between throttle up and throttle down it needs to be able to like smoothly do that yeah i understand carburetors now better way better yeah i i guess nobody actually 100 understood well i couldn't do what i wanted to do i could not make it run because it wouldn't hold its setting in the position but man it worked so when you just went wide open would it run wide open well i didn't want it to run away try it we got a fire extinguisher well you got centrifugal forces you can tear the engine up you can run way too fast you got governors you got throttle you got control in a factory built carburetor that we don't have here you could get you could i could get hurt we could tear the end in all the pieces okay by supplying more it'll run faster than it's designed to run let's run it steady state as fast as you're comfortable i'll try to but i can't i'm gonna have to put a finger right there i think it'll just start right now without a choke put a finger or a finger a finger a piece of tape to hold the choke open i think it'll start tell me what do you want me to trigger i just triggered all right i got it so kill it yeah or you won't let it run for a second whatever you want it's running that's so cool you just kill it with your thumb all right so i triggered that it's awesome [Music] so you you ran the choke at about halfway what would you change on this design like now what would you change i would make the controls stiffer so when you put them in position they would hold themselves okay that's what i would do that's what those ridges were an attempt to do is to make detents but you're saying we need a finer resolution control the engine sucks the throttle you say the engine sucks the engine sucks the throttle open yes oh does it it does run away if you don't physically restrain it it gets faster and faster and faster really there's no governor yes and that makes sense yes that makes sense because the the load is asymmetric on that isn't it yeah it's trying to pull that open okay and i'm holding it there so that it does not because i don't want it to run away right oh that's so fascinating what if we now get a tight lens and we get really really close just from the entrance of the throat of the of the venturi there to the back side of the throttle where you can see the actual squirt you can see the squirt of the fuel come up can you see that now barely can you zoom into that yes sir i can i can get a tighter lens we can zoom in and we can see the the fuel come up into the venturi and then we can see it vaporize yeah you'll do that yeah okay this one is running it way slower so it's providing more context okay so this one's running at like if i recall 1500 frames per second okay so you can see what you're doing a lot better but normally you feel how tough it is to move this yes that's why the throttle runs a steady state that's difficult to move on purpose so that the engine can't get all the juice it wants so that the how hard it is to move a throttle is a design on purpose yes they do that to keep a steady state yes because you want to be able to set the throttle and leave it there yes okay i'm a small engine yes on a small engine i'm learning a lot so that's cool have you ever thought about that no have you ever thought about have you ever thought about an intake like affecting the throttle because it's going upstream no no usually your foot on a car controls that throttle and the spring returns it so it's always in a position that your foot controls but on an engine like this you set it at a particular rpm and it remains there by itself if the engine did what it wanted to do it would suck all the fuel it would want and it would run away that makes sense because it's a it needs a negative feedback and if it's not there it'll just yeah but now people who actually work on small engines could give you a lot more educated words and what you're getting i don't want a person that is paid to work on small engines i want to learn about carburetors from my dad you could have picked anybody going down the street i think you're doing all right we got more information i think you're doing just fine [Music] you feel you can feel yourself learning too oh yeah i'm learning go for it i it up and down a little bit can you kill the throttle kill the punch go up on the throttle yeah it's running too rich it's running too rich you can smell it okay almost kill it can't you almost kill it that's a good carburetor we got some crazy vortices do it oh i see them [Music] so that is on the inlet side turbulent flow is avoid for disease turbulence yeah absolutely you're just trying to get me riled up because you know derek might watch this video yeah i like derek i like derek too so all right so look at that there's positive pressure oh did you see that look okay let me back up okay so the oh do you see that okay look i'm gonna back up and okay hold on for the purposes of the video we're on frame minus two three seven two three [Music] do [Music] look at that you see when so okay i'm going back i'm going back to where the intake stroke starts so look at that so the fuel is coming up into the jet that's the main jet right where's that entering right there yes it's coming straight up in the middle of venturi and then the intake blows air blows air across it but that's not really how it would work because it would really only pull fuel up when the second unless there was a delay in the line unless the vacuum delay could there be a vacuum delay like i put negative pressure on the line i start the fuel coming up the straw and then i shut it off and then the fuel keeps coming up and then the intake stroke so it squirts a little fountain up and then and then the fuel air i mean it's blown away and the air blows it away the tornado gets the fuel right but we agree this mixture is way too rich correct yeah i think so look at the uh look at the blue tape on the front you're trying to there's so much yeah you're going to have to analyze it let's see it our yeah we're going to have way up the bowl he just wants the engine to run he doesn't want to like analyze it i just want to see how much fuel was in the bowl the needle and seat works it's just almost submerged i don't understand why there's a little bit of backflow into unless the the intake valving totally closed yet you're you're coming up to push things out the exhaust and the intake valve hasn't closed yeah maybe that's one option look at all the stuff dancing down there let's run it again and just look at the top of the fuel in the bowl i just want to see what that looks like ready ready start yes sir hold on hold on kill it i just saw something really cool when i triggered it just looked cool so i i just i was like i want that [Music] so [Music] do [Music] it's not going low enough to disconnect the uh the needle staying seated [Music] well now the needle usually has a spring in the end of it for it looks like a westinghouse washing machine oh it does we're getting oscillation on the inside because our post that's holding the float is not rigid enough all right we're learning i need to machine this out of aluminum is what i need to do i need to machine the whole thing out of aluminum then you can't see it well we can still put the face on the front okay yeah you know what i mean i mean we've already seen what we want to see but i kind of just want to know if i can do that but you're getting to the point where an artist never gets through with this painting he finally has to abandon it right right you're going to get to that point you you will never stop evolving and perfecting your design so your purpose in the beginning was to get high speed shots of a carburetor i think you've accomplished that i think i didn't think you could do it oh come on each time you see a shake is a stroke isn't it no i don't think so you don't i think it's a vibration mode i think it's a harmonic you think it's a tuning fork i do yeah it's it's shaking okay i see you're that's when he's put his finger up there i see so you got an intake stroke there should be four should be intake compression power stroke exhaust so you should have four strokes for each and you do have if you look at it right there one two three suck one two three suck one two three suck it's four strokes so you're saying the vibration of the float is the piston turning around it's top dead center and bottom dead center you're pretty smart for a redneck well that's why they call it four-stroke he's right isn't he one one two three does that mean the engine is not tuned like it's not balanced correctly no the engine is doing what it's supposed to do top dead center intake compression power stroke it goes up exhaust the other thing consider two is the carburetor sticks out from the engine and six seven inches whereas so it literally is a tuning fork whereas this old carburetor yes that carburetor is bolted right up against it and it's two and a half inches long moment on you're much i'm just gonna save this because we can what kind of a float does that have turn that whole bow right there is it a brass float so this is the original carburetor we're going to take the bowl off and i think what you'll see i don't know what the float's made out but i know this right here is your jet yep it's much smaller there's not a lot of stroke there either it doesn't have to be just so that's the float goes like that yep so we've got a much larger carburetor if it hasn't run in a long time of course you use carburetor cleaner but those bread tie wraps is just the right diameter so all you're saying gets right down there and stops it up now i need to go work on my generator at home while i'm thinking about that okay so now we understand the carburetor on a macro level we have built a functioning carburetor which is awesome but now what we need to do is i want to see the tight stuff like what happens when that jet of fuel comes up and the air intake comes over the top of it what does that look like [Music] there we go i say we just do that right yeah i'll do it quick for the plastic is hot yeah go so ahead yeah everything is hot there ready uh yeah here goes good work run it lean as you can all right that's good you know as long as i could get that was the choke open and the throttle was wherever [Music] [Applause] look at this oh wow you can see a drop coming out so again you can see a drop of fuel coming out [Music] and get ooh yeah i know that was suspended a drop of fuel suspended in the air and then the suction comes and breaks it all up derrick is gonna love that because of turbulence yes [Music] [Music] that's changing laminar coming in here too turbulent converging diverging nozzle so a carburetor is just a rocket nozzle it's a rocket nozzle that's what it is i mean you're speeding up watch it oh oh oh oh it's a little drop and yep it's coming up and here we go oh look it this is a drop suspended it's a suspenseful suspension [Music] minus 17 200. that's cool that's cool so it's not vaporization like i thought it's literally mechanical mixing it's not anything like i thought it would be what did you think it would be i thought it would be just a vapor-like aerosol coming out of a hairspray can that's what i thought but now this liquid spit it in the air when it starts accelerating the airflow through there it breaks it all apart [Music] so why why does every car not have a carburetor because cold weather they suck fuel injectors are much better uh carburetors with an art not a science yeah if you got one running good at high rpm it doesn't run good at idle you get set for idle so the ideal solution is a fuel injection system yes okay so how does a fuel injector work i don't know i don't know yeah i think you do know it sprays it it sprays uh fuel into the directly into the combustion chamber i think i'm sure it is yes and not many people that i know can say that they have made a carburetor from scratch it's pretty cool isn't it yeah [Music] i wouldn't necessarily call this scratch well built some pieces of material to a functioning carburetor maybe in the lab somewhere carburetors run pretty good because you have not flooded the spark plug out you're going to pull yes sir she's hurt like a kitten got it wow [Music] do so that jet made it all the way to the top of the venturi we're running way too rich it was running good what we see and what we hear you know we don't know what the engine really needs because it's never been looked at before that's a good point so you're saying this might be normal yeah hey we are rich the way it's sputtering it is rich well look at it slapping against that where yeah i think that's a 3d printed valve and so i think we're starting to uh be beyond the integrity level of it that secondary vortices down it's really mixing it up it's it's about mixing isn't it it is mixing yes well you're increasing turbulence going around that thing so you are getting a secondary yeah it's like putting a second mixer in the cake batter that's awesome so now i'm going to get what happens right when you pull the rope for the first time when there's no fuel in the carb to when fuel goes in let's see what that looks like he's getting close to not being able to turn it off that's good it's fun that we almost couldn't turn it off there's a little bit of risk here virtual motion machines that's fun okay this is a tighter shot we used more fuel that time oh look at this what [Music] so this is the first pull so it was flat the reason it's running at an angle like that is because of the sucking air by it even though we're trying to close it off so we've got to design the the butterfly to be stiffer look at this so on the intake stroke here it deflects you see the rope how cool is that you can see the rope in one frame [Music] they're in the foreground and you see the carburetor i could not have imagined a shot like this oh wow yeah time to uh time to mill those out of aluminum i think that's pla so i bet that pla is getting broken down by the by the gasoline yeah okay okay because it wasn't that flimsy to begin with no we're at the limits of our testing i think oh oh you can actually you can see the fuel coming up in the in the straw and the jet look at that you can see you see that the flow rate there you can see everything if that that butterfly i call them butterflies what would you call it yeah if that butterfly was milled out of aluminum that that'd be pretty good not start it might not start that's a good point what do you think dad it's a lot of work it's what i think is not as fun as what i thought it would be from a distance when i'm sitting at the keyboard and reading comments uh it's fun but taking the video shots i don't even want to think about editing it's a lot more work than what i thought it was really really yeah yeah it's a lot of work yeah and i know you've taken 100 shots to get one good one but still you got to get the bad shots don't you you have to yeah absolutely yeah this first time you've seen me do this no you've seen me do a little bit of this now i have i have but i'm tired today really you're more empathetic today hey i'm retired i'm supposed to be taking a nap right after 11 o'clock second nap of the day right oh man hey we didn't need the fire extinguisher that's good but we had it that was an insurance policy okay trying something crazy we removed the choke right here just pop the choke out and then we're just going to look straight down the barrel to see what happens there but in order to do that we have to get the proper mixture to start the thing which i now understand how to do with this blue tape over the end here so a lot of hands to try to get a really interesting shot but we're going to try it i'm going to block about three-fourths or at least half of it yeah all right so that's going to lean our mixture right yeah hold on you ready yes sir are you pulling focus i'm gonna have to once it's running yeah we're gonna hit where's that that doesn't work anymore it ain't gonna run we're not getting any [Music] right now cover this whole hole all right nope i didn't get it i need a little bit more time to focus yeah okay can we jump can someone jump in and grab the throttle yeah you're gonna have to meter it with your finger there yeah so i'll meet her with my finger and you grab the throttle throttle's wide open right now but it shuts off automatically so if you grab it and shove it back the other way i'll be pulling it this way other way that way keep it there yeah shoot let's do that with tape what am i thinking that's all right i can do it hold on it'll never suck it to begin with does that mess up the shot coming off or anything i love that we understand uh carburetor carburetor so when you do that just drop the rope okay all right ready got it i can literally throttle it with my thumb yep ready ready did you get it die engine i don't want you to have any oh i'm getting it oh my goodness there's your favorite there's your vapor i saw the vapor there's a vapor right there got it where it coming out no and the intake manifold oh yeah whoa that's that's vapor yep so that's what happens when you get vapor lock i don't know i don't know i don't know i've just heard vapor like before i don't know what's going on okay so vapor what just happened is dad cranked it i covered i choked it with my hand he was operating throttle for a second there we were we were reviving we were insane so i was running choke dad was running throttle trent was trying to frame the shot [Music] i just hit your mic it flattens the dropout it does it flattens the dropout and it distributes it look at it yeah what's that oh that's really freaking cool it's the drop comes up when the intake air hits it it flattens out we could not see that from the 90 degree angle no i now [Laughter] i now have a three-dimensional understanding of how carburetor intake air interacts with the fuel coming up in the main jet that was worth it did you have that understanding so imagine if that geometry was circular then i wonder what effect the square is having on the house oh you mean that the tube that we made so that we could see into it if it was a pipe yes yes it would distribute it evenly that's unbelievable it's it's taken it's serving up a raindrop and then slapping it serving up slap serving up slaps it's kind of like your levitating water drop studio um we can get closer that's so cool we can get closer that's awesome have you already saved this uh to the flash i've already said flash this the mag is full okay all right we'll save it to the we don't have any more fuel in there we're going to try to get that shot but tighter [Applause] dude dude that was intense that was what his carburetor tries to do is increase the surface area on a molecular level right all right what do you mean in order to get full complete combustion you need all the surface area that you can get at the fuel because ideally you have an oxygen molecule right next to a fuel molecule and when the ignition happens if you got a good proper mix i think vapor is that white stuff that we've seen at the end of that run it's atomizing it okay so i'm pulling that yeah i can get it started i just want to see that are you focused on the hump down there what's our what's our uh aperture hold on if i come in tighter if i can give you more light would you take it how's that yeah that's great but i couldn't get to this turtle right let me pull it up a little bit oh how about we crank it and then i'll bring the light down yeah let's just do that go for dad let's get focused on letting it run yeah ready yes sir what was you're going to hit the cardboard of the rope there you go okay let it have more air ready yeah yeah okay hold on this is good but i'm gonna save a little one okay i'm saving probably 10 seconds okay we're okay it was out of fuel put more in it did you get a good shot i think so okay [Music] carburetors are amazing they're on all kinds of small engines one thing i really like to think about is there is going to be a time where there is a maximum number of carburetors on the planet right like brushless dc motors are on the rise obviously because battery technology is getting better so the carburetor has been an amazing thing for years and years and years but it's going away it's never going to completely go away i don't think because the amount of power density you can get for a volume of gasoline i mean i think it's here to stay but it's just really interesting to think that this thing that basically ruled the 1900s is probably on the decline sometime soon i don't know when but that may happen anyway we have a video coming up on fuel injectors and we've already filmed it it's really really cool my buddy jacob is a diesel mechanic i went took a high-speed camera it's gonna be really cool i hope you enjoy that but thank you for watching this video here on the second channel it was really fun to be able to share this moment with my dad with you dad i know you're watching um i appreciate you teaching me all this stuff through the years it's it's great you've made my mind what it is and i'm grateful anyway thank you so much i'm destin this is smarter every day too you're getting smarter every day have a good one bye you

Channel: Smarter Every Day 2

Views: 284,106

Keywords: Smarter, Every, Day, Science, Physics, Destin, Sandlin, Education, Math, Smarter Every Day, experiment, nature, demonstration, slow, motion, slow motion, education, math, science, science education, what is science, Physics of, projects, experiments, science projects, engine, carburetor, carb, fuel injection, lawn mower, small engine, engineering, how does it work?, How, fatherhood, parenting

Id: TWfss7z05no

Length: 78min 42sec (4722 seconds)

Published: Wed Jun 30 2021