• Home
• Videos
• Dangar Marine
• Johnson Evinrude Carburetor Rebuild

Johnson Evinrude Carburetor Rebuild

Today's video is about servicing the carburetor from a Johnson 30 horsepower outboard and is proudly sponsored by MarineEngine.com

Johnson Evinrude Carburetor Rebuild – Video Transcript

Hey there Dangar Stu here, today's video is about servicing the carburetor from a Johnson 30 horsepower outboard and is proudly sponsored by MarineEngine.com.

We'll quickly remove this carb but then we'll just take it over to the beach. I've already removed the primer solenoid from this outboard so we don't have that to worry about but we've got our throttle linkage here we'll just pop that off leave that up here. Now this is mounted with two bolts but this one in here looks quite hard to get to with the starter motor in place so I think I'm actually gonna take the starter motor out in order to get the carburetor off. We'll start with this nut here which is a half inch nut and then looks like there's a smaller bolt that goes through here but this is also where they gear selector linkage is pivoted from so we might undo this as well. olt on the side was 7/16" do you select two brackets 5/16" I want to take this other 5/16" bolt out but I can't get to it because of this little stop.

It looks like an adjustable stopper here so we'll unbolt this here from the exhaust cover looks like down here this is actually a part of the engine block and this is the starter mount so I'm going to take this bolt out. Start to wobble now so I'd say this is the last one this is an 11 millimeter spanner side say it's a 16 spot looks like one of those rare times the ratchet spanner actually kicks in and I can use it alright take this main positive lead from the solenoid. So I've just put everything back loosely just to save me remembering where it goes and save me from losing anything. This now gives me good access to the nut on this side, this one I just got to pull the throttle out of the way I can get to that easily as well and these both half-inch nuts this is hitting the carburetor here so I'll just back the other one pull it forward keep going so same thing either side. Both the nuts have bottomed out now pull the carburetor forward go a bit further just put these nuts back on the studs then we'll take this fuel line off from the bottom and get over to the bench. So a little bit harder to get off than I'd hope but not too bad.

This is the kit I have to service this carburetor there's the part number there I'll put a link in the description to the MarineEngine.com website if you want to buy one. So what I'm going to do first actually just open it up see what's in the kit so we know what we need to keep and what we're going to be replacing. We've got three gaskets here and your float in here, we've got a new needle and seat to go with the float then in here we just got an assortment of sort of seals pins caps all that kind of stuff. So we'll see how we go I'll start by just pulling this apart and pull the victim apart strain and we'll give the jets and everything a bit of a clean. See conditions and sort of play it by ear really to start by just taking this top cover off.

The basic principles are very similar with all carburetors but they do have their own little you know ways of achieving certain things and I've got to confess I'm not super familiar with Evinrude carburetors but how hard can it be. It becomes a bit oily on the top here we got the fuel in from the primer and on this side we've got a little air orifice or clean-out. While we're here I'll do all the cleaning at once or just disassemble to start with. On the top here's the gasket to seal the top plate once again pretty oily underneath so it'll be good to give it a clean up. This gaskets a good match for it so we can safely sort of get rid of that on this side. Here we have an idle mixture screw normally what you do is wind them in count how many turns in it is and that way you know how many turns out it has to come back out when you put it back in. In this case it looks really compressed so I doubt it's gonna go in very far which makes me think it's probably not where it should be anyway.

So I wound it in we'll see how many turns it is take it out but I don't think that's right so it's really only one of the bit turns out so I'd say it's not out far enough. But then chewed up properly once it's all back together and running so mixture screw and the spring now we'll take the float bottle. Once you start taking screws out from multiple locations it's good just to compare them see whether you can get them confused in this case they're a different diameter so you can't get them in the wrong place. Really all you're looking for is screws that have the same diameter same thread pitch but a different length that's where you can get into trouble. Float bowl looks nice and clean that's good there's a drain plug in the bottom here I'll take the drain plug out because it's got a little fiber washer on it that will replace with one from the kit. Inside here behind, so it's actually in this section here but you access it through the drain plug, is the main jet for this carburetor so we'll take that up.

Next the trick we're getting these jets out is to find a screw driver that fits in but make sure it only just fits that way you've got as much blade as possible in the jet itself which gives you the least chance of damaging it. So here's the jet out now it looks reasonably clear. So around the float Bowl we've got another gasket so we'll take that off and pretty confident got the right kit now because this matches perfectly - so we'll put that aside to get the float Bowl itself off. We need to take this pin out here so we can just pull that out, and that's to pin the float pivots on and there you can see hanging off it here's the needle and the seat.

The idea with this little needle and seat is it's a valve to block the fuel off as this float rises up as the fuel pump puts fuel into the bowl here then the needle pushes up into the seat and blocks the fuel off. As the fuel gets used up it drops and this little valve opens more fuel can come in. The little needle and seat kit has the needle here the little clip that holds it on and the sealing washer to go around the seat. The pivot pin for the float actually was included in the main kit here. When the bowl goes on is the top section here that seals around here and there's another seal there we'll be replacing so we'll take that off and replace that as well. Taking out the seat for the float Bowl it's a good opportunity to actually show what I was talking up before which is it's got a slot in it obviously your screwdriver needs to fit in it in this case here though you can see the screwdriver. I've got at the moment slightly smaller than the slot so what I'm going to do is a bit larger to make sure we don't damage the soft metal of this seat.

Yes in this case we're replacing it but it's good practice you can see here this screwdrivers pretty much the same width as a seat so I'll use this one all right there's the old seat and then there's the old sealing washer. About the only other thing we have in our kit that we can replace is this little retainer here it's pushed onto this shaft and it retains this spring here. There's nothing wrong with that so I'm just gonna leave that in place so fiddling with it. All right before we start putting this back together I'm going to give it a bit of a clean so I'll start by just spraying with a carburetor cleaner then I used some compressed air. I'm going to start at the top here you'll see there's a couple of very small orifices here so I'm putting some carb cleaner down here down here down here and then we blow it all out. If you don't have an air compressor you can actually by compressed air just in small aerosol cans and it's a great way just to do single carburetor cleans like this. Probably lasts three or four covers to be honest.

This here is the hole where our tapered idle mixture screw so I'm definitely going to get an extra carb cleaner in there at the center. Here is the emulsion tube that helps maintain the correct air-fuel ratio this is affected by how much fuel comes up here so this is why it's really important that the needle and seat close off at the correct height. So we'll talk a bit later about setting the level for the float as well. Alright then we add the little air orifice from the top it looks pretty clean but while we're here. With these large jets and orifices you actually get sets of carburetor cleaner brushes so I'm gonna find a brush that just fits in like this one fits quite nicely it's tight but it fits through reasonably well and then we'll clean it out with the brush as well.

So in the case of an air orifice like this if it's blocked up you'll be running too rich and in the case of a fuel jet if it's blocked up you'll be running too lean. Now everything's been cleaned out and start putting it back together. Often with these kits and definitely with this kit you end up with a lot more parts than you need and that's because they cover some a range of outboards. So we'll start here by replacing the original fiber washer for the drain plug. Before we can put the drain plug back in I need to put that main jet back in so we'll grab that drop it in. With these Jets they just wind all the way in so you wanted to be snug you don't break anything but you don't them coming loose either they're not like idle screws where they need to be set to a particular position they just put all the way.

All right now I can put the bowl drain back in with its new washer around the emulsion tube we had another seal which was this one. So grab a new one of those and then just push it down to the tube. Next I'm going to install the new needle and seat if you have a look at the old needle there you can see this little hook is looped around it and then it slots over the arm for the float. So I'll install that bit first, so this end here is the little hook it just clips on to the needle like that then once the needles free to hang we can put it onto the float I'll get the new seat in.

Before we do that though and there's the little ceiling washer that goes around it and just snug it up. One of the things that can throw the float level out really quickly is just simply having it in the wrong way around so in this case this cutout you section goes down into the bowl. But if you're doing a different carburetor just pay attention to which way it is when you take it out, so if this section is down we need the needle pointing up like that so it's upside-down. But that's the way it's going to be in the boat once you've got it all rigged up just drop the needle down into the seat like this, and then I'm going to go fetch the pivot pin that goes through here. Doesn't look like it matters which way it goes through on this one so you can push it through from either side.

This is the point now will you be setting your float level before you put the float ball back on if you hold the carburetor upside down you can then measure the distance between the base of the carburetor here and the top of the float Bowl. Here in the case of these Johnson Evinrudes is actually a tool that goes over the top that you measure it. Again it's sort of arches up and over and touches here but I don't have one although the service manual says to put the special tool on what I'm reading is it needs to be level and you can see here it's dipping down a little bit of the front so what I'm going to do is bend this arm here until this is sitting level with the body of the governor.

I'm going to do this gently a little bit and what I don't want to be doing is sort of flexing it up going back up you know and keep overshooting and enough fatiguing it you can see here now it's sitting much closer to level. It has overshot maybe slightly but I actually did read that it's better to have this end slightly up so that's where I'm gonna leave it. The other measurement is when you hold it up how far does it drop down and you adjust that by bending this little tab here on the back with the carburetor hanging this way. I read it should be between 28 and 41 millimeters this way and it is so I'm gonna leave that now I'm just gonna put the new float bowl gasket on and screw the float bowl back down. For the screws for the carburetor bowl the manual calls for a little bit of Loctite or Threadlocker on the screws so we'll do that. As always these screws I'm just going to tighten them in the diagonals keep the pressure even keep them snug so the gaskets do its work. I'm not gonna crank them so hard that I distort anything but I don't want it leaking.

With the idle mixture screw I'm just gonna put the spring back on and then wind it all the way in and then wind back out about two, two and half turns. We'll tune it up properly once the motor is running again so seat it all the way down gently. I find it easiest to count half turns so I'll go five half turns back out getting the correct orientation of the top cover gaskets much easier by putting it on the cover first. You can see here there's a little pin or a dowel here that goes through a hole in the gasket that's good like that, same here made in a plastic snug but don't distort it don't break it. Last thing now is just putting the air bleed orifice back in the top cover and we're pretty much done.

The last gasket we have left is the one that goes between the carb itself and the engine. It's really important this seals well because if air can get between the carburetor and the block you have a vacuum leak which means the engine is going to be running lean. You've got the correct fuel air mixture coming through the carburetor then you've got extra fresh air meaning you got too much air not enough fuel. This has got a bit of old gasket left on so I'm going to clean up both the carburetor and the block before we put it back on. Now both surfaces are clear we're just going to put the new gasket on dry and then pop the carburetor back on. It's a little bit fiddly getting these nuts back on due to the shaft of the butterfly valve being in the way but if you keep the carburetor forward get them started then you can just start to work the carburetor back towards the block. As you do the nuts up then just do them up with a 1/2 inch spanner.

We want these reasonably snug to avoid that vacuum leak we were talking about earlier. At this point in proceedings we'd be reconnecting the primer are reconnecting the hose from the fuel pump all that kind of thing, squeezing a primer bulb and looking for leaks. Obviously just need to sort that out, in this case I don't have those on things connected yet because we're giving this a major the overhaul but you get the idea.

All right well I hope this video has helped you if you're looking to service the carburetor on your Johnson Evinrude outboard. We will push on next and do the fuel pump but until then take care see you soon.