Craftsman Mower Starts but Won't Stay Running - FIXED!

how's it going eliminators today I'm gonna be showing you how to fix one of the most common issues that plagues lawn mowers come springtime so let's get right into it so I have a craftsman mower here and this mower has a Kohler courage 149 cc engine and my customer complained that it would start up and then it would shut off right away now this engine features an auto choke system so there is no primer on it and when we go ahead to pull it it fires up and then it shuts right off so I've pulled the mower into my shop now we're gonna go ahead and remove the air filter cover it has a brand new air filter installed on it and down here we have two ten millimeter nuts that we're going to remove now once you remove those nuts that you can disconnect in the breather tube as well as the fuel tank vent tube back here so now that we can see the carburetor I'll just briefly explain how this system works we can see that here is the choke plate and the choke plate is set to the closed position when the engine is cold so that when you go ahead to pull your recoil rope to start your engine this blocks off the air which is going to rich in the mixture because now you're getting less air more fuel it's also going to create more suction which will help pull fuel up the main jet into the carburetor now you're going to notice that this choke lever up here has a little tiny rod attached to it that attaches to this rod here which goes all the way back down to that housing right back there and you guys are going to notice that that housing is bolted to the muffler so inside of that little housing is what's known as a bimetallic strip and the way it works is basically the same as your thermostat inside of your house works depending on whether it's hot or cold that little strip inside of there which is coiled will either expand or contract which will in turn rotate this rod right here which you guys saw me moving earlier which will in turn open or close the choke plate so a very common issue on these auto choked lawnmowers basically what happens is you go to start your machine and the choke plate is closed so it increases suction allowing feel to go into the engine it fires up the choke plate opens up and now you've lost that extra little bit of suction and the engine shuts off inside of the carburetor you see that little brass tube there that's the distribution tube and on the bottom of that tube is going to be the main jet if your main jet is completely clogged your engine won't start at all because it won't be able to draw any fuel from the bowl of the carburetor so what we have here because the engine starts up and then shuts off is that the main jet down below likely has some gunk built up into it but is not completely clogged in order to remove it this choke mechanism you're gonna have to either come over to these two Torx screws this one's hidden by the choke plate there remove those and then you can simply pull off the whole mechanism at the carburetor or you can simply go to the ten millimeter nut here and then you can remove the entire assembly all at once I prefer to come down to the Torx screws and remove them so that I can separate the carburetor from the rest of the mechanism so it just makes it a little easier while I'm working on it now once you get those two Torx screws removed you can simply pull on this little rod here and as you pull off the carburetor that should just pop out it simply just hooks in to that choke leaver there now we can go ahead and remove the entire carburetor from our engine bring it over to our workbench for disassembly now as you guys can see the carburetor here on the outside is packed with quite a bit of gunk so what I'm going to do just to make it a little easier on myself for the disassembly purpose is I'm just gonna go ahead and clean this up there we go that makes it a little easier for me to talk about - what we're gonna do here so the first thing I'm going to do is come to this little Phillips screw here now a little trick that I tell people when disassembling a car but if you don't know the proper setting is just go ahead and thread in the screw first and count how many turns it is until it bottoms out and then you could go ahead and remove it and when it comes time it for reassembly you can thread it in until it stops and then back it out the number of turns that you turned it in your carburetor will then have the same setting that it did when you disassembled it so I'm going to go ahead and remove that throttle back stop screw now and once that's out simply come to the pilot jet here and use slotted screwdriver also known as a flathead to just pry up that little pilot jet and then you can go ahead and just remove it and set it off to the side for now next up you're going to use a ten millimeter wrench and go ahead and remove the bolt that holds the bowl onto the carburetor you can then go ahead and remove the bull as we can see there is a little bit of gunk built up in the bottom this could just be broken down bits of fuel now just to go over the things that aren't wrong with this engine we know that the carburetor ball wasn't leaking so we know that the bowl gasket is fine the carburetor wasn't overflowing with fuel which means that the needle valve it should be sealing so if I was to perform a pressure test on this carburetor it should pass we know that the engine ran even if it was for a brief moment which means that the coil is producing spark and the cylinder is producing good compression and we know that the valves are shimmed close enough to the spec that they're supposed to be because if the valves were loose then it would be hard to start and this machine starts on the first pull every time it just simply shuts off afterwards so it's safe to say that this engine just has a fuel delivery issue so the next thing we're going to do is come to the main jet here you're going to notice that that is slotted so we're going to use our slotted screwdriver to remove that now once you go ahead and get that jet loosened off simply flip your carb upside down give it a tap and the main jet should come out and the distribution tube should come out as well now I've brought the main jet over to the window here and just looking at it we can see that the main jet does have some gunk built up into it so as I said if this main jet was completely clogged the engine wouldn't have started at all so what's happening is as that choke plate closes it's increasing the suction which is helping draw that feel through that small hole in the main jet allowing the machine to start up but once that choke plate opens up there's less suction and again the engine just can't pull up the fuel through that main jet now I've used what's known as an oxy-acetylene tip cleaner they come in a pack with a bunch of different sizes so you can pick the size that best fits your main jet and we're simply just going to go ahead and push that through to clear out the hard bits of gunk that are in there now if you don't have a set of oxy-acetylene tip cleaners you can go ahead and use a can of carb cleaner so here I have some gum out small engine carbon choke cleaner and you would simply use that to blast out the gunk inside of that main jet and looking through the main jet once more you can see that the hole has now gotten larger and will allow the proper amount of fuel to go through it and the pilot jet normally gets clogged up much easier because it's a smaller hole than the main jet now for the pilot I've actually made a small little tool here basically it's just a small piece of wooden dowel and I've broken off a piece of metal from a wire brush these wires are actually hardened steel whereas with the oxy-acetylene tip cleaners they aren't hardened so you're gonna notice that this little end broke off here and it makes it much harder to push one of those through a small pilot jet and using the same method we're simply going to take at that piece of metal and push it through the pilot jet until you can see it on the other side there and we now know that that hole is clear now once you clean your carburetor you put it all back together if your engine surges which means it's going to be revving up and down you can drill these out to oversize the pilot jets which will allow your engine to have just a little bit more fuel on the idle circuit if you guys want to see a video of how to do that I'll link it in the top right of your screen as well as in the description down below and I'll also link to a video where I show you how to properly remove a stuck float rod and then coming down to the distribution tube here you guys can see that it's perfectly clean so lots of fuel will be flowing through that now at this point if you wanted to you could most likely go ahead and reassemble your carburetor put it all back together if you were on a budget it would most likely start up and run just fine but because I'm doing this as a business and I want to give my customer a guarantee I'm gonna go ahead and disassemble the rest of the carburetor get it cleaned up in my ultrasonic cleaner so that I know it's spotless inside and out now while the carb is cleaning in the ultrasonic cleaner I'm gonna go ahead and remove the fuel line clamp drain out the fuel tank flush it out make sure there's no debris in there now as I'm draining the fuel here you guys can see that it is draining into a jar now let's say that you didn't have a clogged jet on your carburetor and it was actually a fuel delivery issue from the fuel tank itself if we follow the line back to the fuel tank here they actually have an inline fuel filter that sticks into the bottom of the tank there so if you wanted to you can go ahead and disconnect your fuel line there go ahead and pull out the little plastic inline fuel filter and then make sure that that's not clogged so you can come up to your fuel line simply pull it out and then that will expose our inline fuel filter here the inline fuel filter actually looks pretty clean we can see that it looks like it's free of debris on the inside as well so all of the sediment built up in the bottom of the carburetor Bowl most likely came from broken down fuel so why now have everything out of the ultrasonic cleaner the carburetor pretty much looks brand-new the fuel filter is nice and clean the main jet distribution tube and pilot jet are clean and the ball is also clean as well so I'll go ahead and reassemble this carburetor going through all the steps that I did just in Reverse okay so the carburetor is reinstalled fuel lines hooked up fuel filter is back inside of the tank and I have 1 liter of fresh 91 octane ethanol free fuel inside of the fuel tank now in all the fuel that we run in our customers mowers we use fuel that has K 100 s + fuel stabilizer in it this will make your fuel last for two years so I'm going to recommend it that my customer buys a bottle of this off of us for 10 dollars and that should prevent him from having to come back next year for service you'll notice that we use a little bit of Gorilla Tape here on the airbox housing and that's simply because these air box covers with the single snap in design don't hold into place they always pop out which results in your air filter falling out so a little bit of guerrilla tape holds that on nicely so I'm ready to bring this outside fire it up and hear how it runs okay so we'll give it a pull see if it fires up so just like that the engines back up running again the lawnmower is fully operational and the reason the jet was clogged was simply just a case of bad fuel so my customer left a fuel in from the previous year it's at over the fall time and a winter time in storage and then come springtime the fuel is no good anymore it gummed up the jet and you end up getting that issue where the machine will fire and then shut off right away but if you guys enjoyed the video think about leaving me a thumbs up you know it really helps me out you can click here to subscribe and click over here to watch one of my previous videos I upload every single week so be sure to stop on by next week check channel out for new content and as always guys thanks for watching [Music] [Applause]

Channel: Eliminator Performance

Views: 39,980

Rating: 4.9361277 out of 5

Keywords: Craftsman, lawn mower, kohler, 149cc, starts but stops, won't stay running, how to clean craftsman carburetor, how to clean kohler carburetor, Eliminator Performance

Id: A23nERLrBAk

Length: 10min 54sec (654 seconds)

Published: Sun Apr 12 2020