How to Diagnose and Repair a Small Engine

is it John happy wife acres and today I want to run through how to diagnose and repair a small engine [Music] this obviously is a chainsaw but the things that I'm going to talk about it doesn't matter if it's a chainsaw or a weed eater as long as it has a small engine could be a push mower so we're gonna go through what it is you need to look for every agent needs three things to run it needs fuel it needs compression and it needs a spark customer brought this to me he knew very little about it I think it had been in his garage for a while so I'm gonna run through these steps to make sure that those three things aren't working and show you what I do when I repair a small engine whether you are a homesteader or homeowner you probably have some small engines and hopefully this will help you alright this happens to be steel oh 41 avy farm boss it probably belongs in a museum it it's almost an antique a lot of metal on here so I've already taken the blade off just because it gets in the way and so we'll get down to the spark plug and I'll first test the compression I remove the spark plug take a quick look at that and actually doesn't look very bad at all it should be kind of a grayish color black but not too black you don't want it to be too white but that's a good-looking spark plug so I'm gonna clean that up recap it put it back in to test compression I use a compression tester and get these at auto parts stores the end goes into the spark plug hole so you just screw that in and pull the cord a couple of times take the reading plugged in just give it a pull so the reading on here after a couple of poles is about a hundred and that's a good number for small engines anything at least ninety up to a hundred and fifteen or so but if you got a hundred you got good compression so don't worry about that the next we're gonna check the spark by the way if your equipment was running fine and now all of a sudden it's kind of it's starting but it's running crappy you don't need to check the compression if it's starting in any way you've got good compression I tested it here because I don't know anything about this machine alright so the next thing is we're gonna check the spark this is a spark tester again you can buy it at auto parts store and what you do is you've got the spark plug in I'm gonna connect it just like I would the boot except this in actually goes into the spark plug boot this is the boot by the way ok and then I'm going to pull the cord and if there's spark then there will be orange inside of that glass window here we go try not to shake it too much turn the lights down so see it a little better all right you see that orange flash so we have spark the electricity is produced in the coil as the flywheel turns so if the engine is turning its producing the spark hey there's no battery on these things alright so we know that it is producing electricity for a spark if you don't have one of these fancy toys you can do the same thing with a piece of wire jumper wire now what you're gonna do is plug the spark plug into the boot okay here's where the gap is right at the end of the spark plug so all I'm gonna do is hook this to the end of not the electrode but to where the spark goes to the ground side and then I'm gonna come up here just hook it to ground all right so I'll just look at their carburetor then when you pull you should see spark jumping across that gap clearly see the spark that says that not only is there electricity being produced but the spark plug is working as well making the electricity go across the gap providing your spark so the beginning I said you need compression spark electricity and you need fuel so we've already checked two of them now we're going to check the fuel the fuel delivery is through the carburetor it's this little square thing here it's always at the end of the your throttle and that's what makes it makes it go fast so I'm gonna take that off and we're gonna clean it it's a very simple procedure just a few things you should know so here we go so these are all built about the same way after you take off a couple of nuts then this will just slide off there's usually one or two gas lines you just have to loosen that and as it's coming off you'll be able to take off the linkage so again they're all a little bit different but pretty much the same I'll just get this off then we'll focus on the carburetor if you have trouble getting it off I use a little screwdriver you just put it in here pull it out and while I'm taking it off I always check the lines and these are very very soft and rubbery like they should be so don't need to replace them but you do want to make sure that if it has been replaced that someone used actual fuel line I guess non fuel line will melt on you and you want to make sure that it's the correct size this thing pulls up and off comes the linkage and now we have our carburetor carburetors again they're all built about the same that we usually have two sides to take off here one there so just take off the screws before I even started I blew all this off with a compressed air if you don't have an air compressor I highly encourage you to get one they're very handy so there's a gasket under here it it likes to get stuck this one's coming off pretty easy so happy about that alright pull that off then on the other side also pulls off if they get stuck I use a razor blade and I just start on one corner and then very gently encourage it to come up don't want to rip this or you'll be buying another one and depending on the the age and the type sometimes they're cheap and easy and other times not so good so the best way to ruin a carburetor on a two-stroke engine is to buy the absolute cheapest fuel that you can it's mixed with ethanol and ethanol tends to just dry things out the rubber but get the premium fuel hmm this actually feels good I'm very happy about that try and get this off again on this one you've got all the time in the world do not rush it trying to find it order it pay for it and that's gonna take away more time but if you can get it off and reuse it should run well for you so for most carburetors this piece right here is what will go bad there will get some dirt clogged in it but a lot of times it's this it's called the diaphragm and its job is to go up and down pump with the vibration it should feel like silk if it's crispy and goes crunch-crunch-crunch it's bad get a new one okay so we got that apart and this right here let's gas in there's a spring under it if you can see this goes up and down there's a little needle valve in here so it's held on by one screw sometimes it screws on this side beside but you want to hold that down with your finger so that spring doesn't come flying out then unscrew and then let everything come out and there's a little little spring there's the needle valve aim the whole assembly the last thing to take apart some carburetors have none some have one some have two of these screws if it has two it'll be marked with an H and then somewhere it'll be marked with an L some you can't screw out because they have limiter caps on this one it looks like you can if you want to check where they are screw them in all the way and count the revolutions that it takes to get there aim so there's a half full and I'm stopped that's about right on this one a half full and I'm stopped so now you know where to set it when you put it back together initial setting going all the way come out one full turn that's about right anywhere between three quarters and a turn and a half then you adjust it once you get it started the one marked H will always be shorter than the one marked L and you can see in this case L 1 is the long one so now the carburetor body is apart and all the pieces are off of it and it can be cleaned at this point I'm going to spray the carburetor body out with carburetor cleaner you can get this at auto parts or Walmart for two or three dollars so what you want to do is you want to spray any orifices you want to wear eye protection here because this has a tendency to bounce back at you this does burn a little bit if it gets on the skin but where you took those high and low screws out you want to spray through there and then the porch you just want to get it clean the gas has a tendency to get either gunked-up or have like a film on it and you want to get that off you can open up these ports spray down in the air just wanna get it clean that's it tell you need hey this dries very very quickly you can blow this out with some compressed air don't use a whole lot of pressure on this very judicious put too much pressure and sometimes things come loose like this this carburetor did not look very bad a lot of times they'll be a lot of dirt around here so it looks like it was very well taken care of it probably just got parked in a garage for a while before someone brought it to me but you do want to want to spray these off just clean everything and then this little needle valve you just usually just run it through some wet towels just to clean the tip of it right there now we're going to put it back together the hardest part about putting this back together is a little needle valve so you're just gonna take that spring drop it in the hole take the needle valve hang it there's a little indentation right here and that fits over the spring so I hold it on the sides and then I just drop this in the hole and collect the spring okay everything's pushed in well I've got it held in with my finger I'm going to come back with the screw and screw that in okay don't be worried if it takes a couple of times some of some are more tricky than others once you get that screwed in it should go up and down right that's good the rest of it is putting it back the way you found it with this thing the metal part always goes down towards the body of the carburetor okay just put the screws on tighten them all back with the throttle linkage back on just get this over the posts slide it down one fuel line the other fuel line and that's ready to go aim so this may look intimidating to take apart and clean and on your car you may never have to do this on your car but on your small engines this is almost an annual activity because do it every spring it's not going to run very well because it's been sitting over the winter you left gas in it and now it's running like garbage so take it apart clean it put it back together it should only take you about 30 minutes at most one thing if I didn't know any history if it's been sitting for a while I'll look in the gas tank and make sure that there's either no gas or if there is gas I flush it out because water will tend to condense after a while in there and water droplets aren't doing you any good they don't like to burn so this one has no gas it's all evaporated out so I'm going to put some fresh gas in here there is no primer pump on this so I'll just have to see if fuel is actually going to make itself up to the carburetor and get it started so I'll put the exterior pieces back on it and I'll take it outside and see if she cranks as I'm putting it back together checking out the air filter and the manufacturers of these will tell you to buy one every year well that's because they make them so if you keep it clean they'll last a good long time just spray them out get the dust out I don't know how it's made a lot of times you could even dunk it in some cleaner just to really clean it out and then spray it as I take it outside of course I'm going to give it a few polls see if it starts if not I'm going to use the engine starting fluid again auto parts store or Walmart a couple of bucks a can just gonna spray a little bit into the carburetor just to encourage it to start get the fuel flowing that's really what I'm trying to do all right take a small screwdriver with me and here are the adjustments this is your idle speed adjustment on steel they mark it la I don't know what that stands for I don't even don't even care to know it just means it'll make it go faster or slower so if you screw that in it goes faster screw it out and go slower down under here are those high on top and the low on the bottom adjustment screws so once I get it started I'm going to adjust these two screws I'm going to screw it in until it starts to falter then I'm going to screw it out it'll run better and then it will start to falter and then I'll go back in and then I will go out until it just begins to falter and stop okay so you want it a little bit to the left of the sweet spot you don't want the mixture to be too rich the high-speed that adjusts your rpms on the high end go at full throttle and adjust that left or right and until it sounds good I know there is a specific specification for this but I don't know what that is won't had that tool so I just go by ear and so should you okay I'm gonna try and start this outside and change so I've got the top off just in case I need to use the starter fluid there is fresh fuel in here and I did do a tank flush to make sure there were no no solid parts in there all right here we go alright there's some life that's a good sign I'm gonna back off on the choke just a little bit and give you another Pole [Music] all right I did that with the chain off I should have the chain on it to properly adjust it but I don't like the chain just zipping around while I'm doing some initial adjustments but it sounds great so I'm ready to call the customer and tell them come pick up your chainsaw I want to take you through the process that I use to diagnose and repair small engines again not the specific model but any two-stroke a small engine a lot of times you go to take it to somebody and you say it's gonna cost me more to get it fixed and if I just got a new one so in this case we've brought an old piece of equipment back to life you can do this okay don't throw your weed eater in the trash every year go get a new one take it apart it's probably a dirty carburetor clean it up make the adjustments and put it back in service I hope you learned something you have any questions you can write and to appreciate if you would subscribe by by hitting that happy wife Akers logo gonna fix some equipment until next time we'll see you soon on the homestead [Music] you

Channel: Happy Wife Acres

Views: 17,382

Rating: 4.9164734 out of 5

Keywords: farm, homestead, small engine repair, small engine diagnosis, small engine carburetor

Id: oCu15YPCPUs

Length: 20min 37sec (1237 seconds)

Published: Sat Jul 04 2020