Total Rebuild Of My Two Stroke Johnson (Engine)

hey there welcome back to farm craft finally got some time we're going to tear this thing apart and see what's going on inside this powerhead let's get through all the stuff we've already seen before i'm going to get the gas tank off and everything take the carb off and we'll we'll get down to the the guts of it well this doesn't bode well i just wanted to take the wires off so i figured i'll pop that head bolt out take this bracket off of here and that bolt is either broken off or stripped one or the other i'm really surprised that that did that i really didn't wrench on it that hard it's strange it still turns with resistance but it's not coming out anymore ah casualty already i guess that just means i i have more time to play with my johnson okay all right let's go ahead and take the intake off and we should see some reed valves behind there so carburetor goes into here so this is our intake which is clean this is clean that's the intake and then this is exhaust and this is where it's all cruddy so looks fine you can see the rings there's three rings on the piston there so these ports are the intake and these are the exhaust now remember the intake goes into the crank case down here and gets pressurized to then move around the bypass which is on the other side into the top of the cylinder above the piston so when the when the piston we're looking at the bottom one when it's going down it is pressurizing the crank case so you hear it and can you see it like i can i hear the pressure and i see bubbles right there [Music] and what i'm surprised about is i do not see any reed valves in here at all i've cleaned this up as well and there's no valves in it so the only valve is the piston moving and i'm pretty surprised to see that but then again like i said i'm not a two-stroke mechanic so maybe this isn't that unusual all right i'm afraid to take any more head bolts off because i'm a afraid of the consequences but we got to do it boy i'm afraid all of these bolts are going to be a nightmare there's one this is aluminum the block and the head i'm pretty sure are aluminum non-magnetic see what heat does i was thinking that was going to mess up the paint really quickly but it did not so let's see hey look at that heat is going to be my friend if that didn't work the next thing i was going to try was to rattle it some with an air hammer just take an air hammer on it and agitate it try to break some of that corrosion loose man they look terrible that one still doesn't feel great i mean there's our head gasket there's my broken bolt it's actually a stud that bodes well i might be able to uh just get that out of there without too much trouble look at how much junk is in the water jacket i guess it's not that bad water would certainly still flow there's a thin piece of metal right there i wonder what that's for maybe like a heat shield what i see is not too bad um but it definitely could use some work that cylinder wall there is clean that's not like a bunch of oil on it or anything i've wiped it off and you can see the vertical lines in it and the entire cylinders the entire surface of both cylinders looks like that and certainly that's not how it's supposed to look so i think what i have i just need to hone my cylinders put new rings in it and i think we're going to see a big improvement let's look at the other one at first i thought all this crud was like totally built up in there but it turns out most of this is just there's there's cavities that are irregular in shape and the crud really isn't that deep it's still good to get in here and get it cleaned out so that the water can flow better but i doubt this was restricting much overall i'd say that head looks pretty good now do you see that broken head bolt can i get it out oh baby is it moving it sure is thought i was gonna have to drill that out when i broke it off that is a beautiful thing all right i'm not really sure if i should take the power head off now which is just uh let me see one two three four i think five fasteners i could then lift that off but then that thing is going to be hard to handle and i've got all these other fasteners to undo so i'm going to go ahead and loosen or take those off as much as i can while it's being held like this makes it a little easier to work on and i'm not using an impact just in case anything requires too much force i don't want to break anything else off i got lucky on that one don't push your luck voila that is really quite amazing to me these are just bronze bushings for seals all right now one thing i want to do is make sure i put everything back exactly how it is so this is the top this is the intake and i'm gonna label this one t for top and then b for bottom and then i'm gonna reach down and put a t on the piston itself and a b you kind of see so there's a there's a flat piece of metal underneath the cap screw and tab is bent so that the screw can't unscrew which of course is a good idea but now i need to unbend it to get it apart and i'm probably gonna break it that's fine i could always make something there's that tab i was talking about so hopefully i can unscrew that now oh yeah maybe i just go ahead and take that piston out and they were certainly not stuck they are very loose all right let's get this next one off and just go ahead and lift out the crankshaft now complete with a part number now if this was a more modern engine and a more critical engine i would be looking to be able to mic these dimensions and get specs i don't think i'm going to be able to get those for this engine really what i'm trying to do here is increase compression there was not a lot of play in anything down here these these bronze bushings look okay so i'm not planning on at this point really doing much of anything with this just gonna clean everything up and get it back together properly after i get new rings and hone the cylinders you can see a lot of lines in the direction of travel clean the carbon off the top which isn't a problem you could just leave it there really the wrist pin has very little play in it it feels good and everything's well lubricated down here i'm pretty happy with what i'm seeing so it's cool to really be able to see it all so again this is the intake and exhaust side so here's our intakes down here so the carburetor was sitting out here when the when the piston goes up creates a negative pressure in here and it pulls the carburetor output into the crankcase then when the piston starts going down these ports get covered up and it pressurizes down here in the crankcase and the crankcases are independent of each other so that each one can be positive pressure when it needs to be so that piston comes down this reaches high pressure and when it gets low enough the piston goes below these ports here which are the bypass ports and if that's not making sense to you i did a video on this i'll leave a link the increased pressure in the crank case then goes up through here through the bypass and comes through those ports and that's how it gets to the top of the cylinder so then the piston starts going back up it's compressing and there's nowhere for it to go the heads here and the spark plugs here so it compresses it fires drives the piston back down and then it goes out the exhaust why doesn't it go out the bypass well because as that piston is going down it's generating a positive pressure in the crank case so the exhaust is just open to atmosphere so this is the lowest pressure place for it to go and that's where it's going to go the exhaust port is also slightly higher than the bypass so the really high pressure most of it's out of the exhaust before the bypass even gets opened if that makes any sense everything happens in the right order it's all by where these holes are drilled and how everything is uh how everything is designed very clever and i'm really surprised there's not a reed valve to be had in this thing couldn't be much simpler all right i need some parts i need piston rings a head gasket and i need to hone these cylinders see you back when i can make that happen they make something called a ring spreader for that but i don't have one so it works been using this stuff to clean up all the areas that have carbon deposits it's working really well i just want to see if i can measure any difference in thickness 68 68. check the other one that one's 67 68. that one's 69 because of course it is all right let's see what our new ones measure it's just under 70. yep just under 70. okay well there's obviously some wear in the rings i'm curious what the ring gap is so these rings have a little step on them that is to make room there's a little prominence on the piston that keeps the ring aligned where it should but what i'm checking is once you've compressed the ring into the cylinder there's a there's a space between the two ends it should be uh pretty small once it's uh in position so i'm gonna put one of these rings in the cylinder up here on this part of the cylinder there is almost no gap at all my smallest feeler gauge is one and a half foul it would not go in there but the thing is uh that's not where the wear occurs you know this is all the way at the top the pistons barely even rubbed there at all i need to come down right by the ports that's where the majority of the wear occurs so let me use the piston to push it down so i'm right at the top of the ports and yeah that gap is definitely definitely wider now i should be able to get a feeler gauge in that so the way this works you use feeler gauges which are just pieces of metal that are specific dimensions down to the thousandth of an inch and you find the one that will slide with a little bit of resistance in that gap in my case it was between eight and nine thousandths in dimension and thankfully the specification is somewhere between five and fifteen thousands so i was well within spec so here's the piston and you can see it's got a little uh nipple sticking out here and here you know because of course my johnson has nipples and another one there so that keeps the rings so that the gap's going to be on one side the next groove down it's going to be 180 opposite and the next groove down it's again going to be 180 opposite and that keeps those aligned and that's what the little step in the ring is four so that that nipple has a place to live so let's get these rings installed so that one's oriented that way the other one goes this way or the next one and there's no difference in any of these rings they're all the same there's no like oil ring or up or down or anything they're just square simple rings square profile probably rectangular not square you know what i mean shut up all right there's one now right now those rings won't stay put they're free to rotate but once they get compressed into the cylinder it's not going to be able to get past that protrusion there i'll just have to be careful when i'm putting them in to make sure that they're lined up right so this is a nice flat fine grit diamond stone and with a little wd-40 i am taking the high spots off of the head and i will do the same on the block doesn't look great but it's nice and smooth i'm happy with that and what has been taking so long was this thing this is a two inch these are one in 15 16. so that will work i have one of the ones with the three stones that go out and and hone your cylinder wall the problem is those tend to catch on these ports and i don't want to damage anything buzzing in there with a drill and you catch on the port and the stone breaks off and suddenly you got a big gouge in your cylinder wall let's let's not do that so these are safer they're not going to uh to do anything with the ports but i had to wait a long time for this to arrive i guess supply chain 240 grit it's not super abrasive i'm gonna put some two-cycle oil in there while i'm doing it this is really what's going to make the difference on the compression in this engine well the rings too but this is the other half of that solution you see that there oh i can even feel that one so i need to hone these out and get all those vertical lines basically out of there you want to replace that with a as close to 45 as you can get cross hatch here's some two cycle engine oil okay and let me do the other side okay i think we might be done all right so i can just barely feel a couple of the vertical lines uh it's not as bad as it was but i'm gonna hone just a little bit more well it's really much better than it was it's not perfect and you know you can't really get them perfect with this kind of hone you need a like a real honing machine that can actually hone it to a specific size this is really scratching the walls but if the walls aren't true if it's not a true circle anymore it's going to stay that way there i think you can see that crosshatch pattern now and it feels nice and smooth i don't feel any of the vertical lines there's a couple like right here you can see one right there but there's nothing to feel so i'm not worried about that i think in order to get all those vertical lines to where you can't even see them i would have to take way too much off with this ball hone you know on camera i think those that cross hatch it looks like it's really scratched up but that feels perfectly smooth you don't you don't feel any of that so now this block is full of grinding dust from the ball home so i'm going to take this up to my utility sink and i'm going to wash it to death okay so here it is all cleaned up fresh white paper towel still comes out white it's quite a bit of work actually to get to this point but you don't want any of that grit left in there because that's just gonna eat up your freshly honed cylinder walls and your new rings if you don't get it out so i decided to check my ring gap again after honing and i'm getting probably between nine and ten thousands and before it was between eight and nine so i've added a thousandth or so to the ring gap all right something else i'm going to do i'm really hoping these are going to be close enough that i'm not going to have to do anything with them but i want to check the clearance i have on my connecting rods there once the cap is on and everything's torqued to spec there is this is going to be slightly larger than that journal right there so that it's free to rotate and that some oil can get in there to lubricate it so you know you put that together how do you measure that that's a that's a tough thing to measure well actually it's pretty easy because some clever people have come up with this stuff this is called plastic age and basically there's a little tiny thread of plastic in here see a little green thread of plastic and we're going to use that to measure this and i'll show you how it's actually quite easy i'm going to cut a little length that will go across that journal and i am going to put just a dab of grease on here to hold that plastic gauge in place there so now that's straight across the journal so now i want to put this on and torque it to spec now i don't want the plastic gauge right on the joint there but right there will be just fine putting it on exactly how it was which is just like this okay there we go all right so they are both torqued to spec so now we're going to take it back apart and see what our plastic gauge looks like and that allows us to tell the clearance inside there when it's torqued down there's really no other way to measure that that little ribbon of plastic spread out that much well then you use the markings on this to tell you how big it is it's between one and a half and two thousandths cool little system that's a very hard measurement to do but uh some clever people came up with this and made it easy so you can see it's wider than the two thousands which the wider it is the the less clearance there is and two thousands is the upper limit of my spec so i'm within spec awesome so when those feel nice and smooth i am going to leave those alone i don't want to take anything off of it and uh get out of spec with my clearances you know if that gets out of spec then it becomes loose every time it's rotating it's it's actually clunking it can cause a knock if it gets bad enough the only thing i see on this for some reason this crankshaft journal here mates with this bronze bearing feels a little bit rough so that one i might just very lightly hit with a stone just to kind of take any high spots off on second thought i'm just going to take a little bit of scotch brite here and just smooth it out this bearing's been working fine i don't want to do anything to jeopardize it this is hardened whereas the the push rod and the cap are not so so yeah i'm i'm here on camera polishing my hard crank yeah i wonder what did that i almost think i'm feeling low spots and i bet you that this got dinged up when it was originally put together because the bearing itself looks fine the bronze part on both halves and if it is depression and not like something sticking up then all it's going to do is carry oil it's not going to really hurt anything and since the bearing looks okay i suspect that's the case so i'm probably being too anal but i couldn't i couldn't work on my johnson and not not at least polish my crank a little bit right it is time to start putting things back together finally so i'm going to take some two cycle oil and put it in the cylinders now i just recently cleaned everything here these are all nice and clean dust free grit free you don't want dust and grit down inside after you've done all this work when i took these pistons out i labeled them so this goes in like that i got to get my rings aligned with the pins which is like that so i'm going to do this by hand i'm not going to use a ring compressor on a small piston like this with these small rings that's easy to do now i am going to have to kind of work and push on these rings to get them in so rather than using like a screwdriver or some piece of metal i've got these wooden dowels that i'm going to use that's not going to scratch anything so this one goes in like this and we're going to do it one ring at a time basically that one just went in now i'm going to be looking at the other ring to make sure it stays in the right spot hey there we go and the gap looks good and that piston is in you see those nice new rings down in there now let's do the other side and there we go now we can look at putting the crankshaft back in but you want to make sure that you get some oil in here because when you first start up you'd be running dry for quite a while not good for your engine this one goes just like that all right i am just giving them a little hand snug and trying to make sure that i'm got them lined up well on the edges start taking these back up well no it didn't totally lock it up all right let's get this other cap around here they look like they are lined up really well i have some permatex anaerobic gasket maker when you're putting a crank case together in my experience there's not usually a gasket there because that's going to change your clearances on these journals right here so you need basically no space between these parts what this gasket maker does is it's going to squeeze out it will fill any any low points any imperfections but will pretty much not leave any spacing in between the two metal surfaces all right i am ready to close this up and hopefully i will never see the inside of this again not hitting it very hard just a tappy tap tap so i'm going to start at the center i'm just going to basically do like that these are 144 inch pounds okay i can hear the suction in the crank case and uh it feels really good turning smooth awesome i'm gonna go ahead and put it back on the stem a lot easier to work on it that way than on the bench there it goes yep just had to get the splines lined up you know that's different i'm gonna have to compare that to previously but do you hear the there there that is crank case pressure going through the bypass and i'm pretty sure that it's more than it was before so that's pretty cool and here you can see the pistons doing their thing so um click so i got a new head gasket and i stoned the surface it's nice and smooth this doesn't look too bad the head itself feels okay but i mean it really has some significant machining marks in it and i'm a little reluctant to just trust the gasket i'm thinking about using this uh this sealant on it here's my new head gasket put some sealant there just a thin coat and then you do the same on the opposite side you let them dry and then you assemble so i'm sure there's going to be a lot of differing opinions on this now i think with a modern gasket you know the manufacturers don't recommend using any sealant i don't think it's necessary some people still do it probably works fine for this these old gaskets a lot of them they did recommend sealant and i think a lot of what i'm i'm seeing on here is remnants of sealant from when it was originally assembled so i'm going to use sealant all right we are ready to put the head back on all right so i've just got two in here just to hold it in place those are going to come back out though because i want to put sealant on these threads service manual actually specs this and you know that stuff that i was calling corrosion when i took this apart may very well have been sealant caked in the threads so i'm using the same sealant it's just this uh forma gasket aviation three it also is made for threads and i'm just gonna put that on each bolt now this is the one that i broke off because it holds this bracket and the magneto which i'm just going to set on top for now i'm gonna fuel okay low speed back in so this is always hard to show this little linkage here gets actuated when you move the speed control it pushes it down and then when you slow it down it comes up that attaches on the carburetor to this right here which is the throttle so i basically just have to put that in and put a little piece of wire which acts like a cotter pin okay all right so i was just getting ready to put the plugs in but curiosity won't let me i want to see what the compression is now i don't really expect this compression to be very good because what i've done is put a cross hatch on the cylinder walls put in new rings they need to run for a while and wear in and we haven't done that yet if i check the compression now and um you know really give them a chance to wear in and then we'll check it again all right let's see what we get 64.65 so i would say you know basically we're unchanged right now so let's finish putting this thing together and see if we can get it started all right so we're all ready to start this thing ah crap [Applause] [Music] we got a fire [Music] so i'd love to tell you that it started on the first pull and purred like a kitten but i'd be lying it was actually a bear to start it's definitely harder to pull which makes sense you know things need to wear in a little bit and i might be getting better compression so i ended up taking the starter the pull starter off and using a drill until i could get this thing running [Music] wow [Applause] [Music] so here we are after idling for an hour it already seems to be running better [Music] [Music] [Music] [Music] [Music] it works so wouldn't you know it this drill that i've been using to do the compression died so i can't use that but i had compared it to using the pull starter and found that i was getting the same results so i'm just going to use the pull starter what do we got there that's almost 90 that's 85 psi look at that that's better hard to pull too yeah that went up to almost it's just under 90. well that's pretty cool let's do the other cylinder right at 90. definite improvement on compression hell yeah now i wish i could tell you that this thing is now a dream and runs perfectly but some of the running issues that i had previously are still there i'm not sure if it is something worn out or if it's just a persnickety kind of engine uh it's taken taken some time to to realize that you really have to you've got two screws here you've got your high speed screw right here that you adjust and then you've got your low speed screw here and i have discovered that when i originally started i have to open up the low speed screw uh maybe even close the high a little bit and do a lot of pumping on the primer get it running once it's warmed up if it stalls i have to lean it out i have to close the low speed screw and when it's running full throttle i constantly have to adjust this high speed screw it doesn't it doesn't want to just pick a a spot and and stick with it so it's an old persnickety engine that's my conclusion i i don't know what else i could do to it uh i've been through everything everything is clean yeah i mean if somebody knows something else that maybe i'm forgetting uh it would be cool to get this thing running a little better but uh but either way i mean it works i mean this is a 1952 engine how old is that thing it this is 2022 so it's 70 years old and uh it still works you know i can still uh still cruise around the pond with it so i'm pretty happy with that i had a lot of fun tearing this thing down and doing a total rebuild on it um pretty cool stuff and uh and really neat to uh to really tear into a two stroke i haven't done that before and i hope you guys learned something i certainly did on this project now this is the part of the video where i tell you do not subscribe to this channel in fact if you have subscribed i want you to unsubscribe do not leave any comments below and whatever you do do not share this video with anybody we'll see on the next one take it easy you know if you watched all the first video and then you watch all of this one you'll have watched me working on my johnson for over an hour straight yeah it's shooting some out so i've been having a blast working on my johnson in front of you guys so here we are at the end of the video keep your johnson in a vice you'll have watched me working on my johnson damn it

Channel: FarmCraft101

Views: 680,586

Keywords: outboard repair, johnson outboard, engine repair, motor repair, outboard motor, antique motor, 2 cycle engine, two cycle engine, antique engine, outboard motor wont start, outboard repair videos, Evinrude, engine rebuild first start up, engine rebuild

Id: Qbe-jwLLN-s

Length: 49min 16sec (2956 seconds)

Published: Fri Jan 14 2022