• Home
• Videos
• Dangar Marine
• Johnson Evinrude Fuel Pump Repair Rebuild

Johnson Evinrude Fuel Pump Repair Rebuild

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

Johnson Evinrude Fuel Pump Repair Rebuild – Video Transcript

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

Now although I'm doing this job on a Johnson 30 horsepower these fuel pumps are pretty common across a wide range of outboards, for example the kit here says that it's valid for engines from 1990 onwards and from nine point nine horsepower to 155 horsepower for both the Johnson and Evinrude outboards So a pretty big section of outboards out there this is the fuel pump. Here on the sides the first thing we're going to do is take it off and get it over to the bench.

To take the fuel pump off we're gonna have to disconnect these three hoses and then it mounts here through these lower two outside screws. I'll take the screws off first to make it easier to get to the hoses. Between the fuel pump and the engine block is a gasket to seal it, well we're replacing that so we can throw that away but I'll keep it until we make sure the parts are correct. Then I'll just put these screws back in the block so I don't lose them now I'll just use some side cutters to cut these cable ties. This one's a bit stuck to the outlet pipes, I'll just get some pliers. With hoses like this I normally try and grip them in the curved section of the pliers and then just give them a little bit of a twist just to break the friction between the barb on the pump and the hose itself.

All right let's get it to the bench and disassemble it. Before we take the pump apart we'll just have a quick look at what's inside this kit. This is the part number for the kit here but I noticed the instructions inside have a different part number I'm assuming that these instructions maybe we're an original part number which is since been superseded. So we've got is a few of these little check valves little one ways. Some gaskets, this is a new gasket to replace the one we took off the engine so we can see straight up there a match, then diaphragm that's a common part that can go wrong. Also got a couple of different rings, it actually says in the kit that you may not need all parts depending on what sort of fuel pump you've got so what I'm going to do is put all that aside for now and then we'll start taking this one apart and see what we need.

As with all things it's best to pay close attention as you're taking it apart so for example you can see here this inlet barb here comes off and it comes at an angle between these two screw heads so you can get to them so that's the way I'll reinstall it when we're finished. I'll quickly pop some gloves on because it's worth noting that obviously fuel sits inside these fuel pumps so if you've used the outboard recently, or even not so recently, it's going to be full of fuel so be careful of that. I'll take the front cover off inside here is a mesh screen a filter that you can clean so I'm gonna pop this out. It looks to me though like the plastic around here is actually broken so we've got one of our O-rings our filter mesh hope it'll show up on the camera but I'll show you the cracks in this housing you can see it's cracked here, here, here and over here so it looks like this cover is gonna need replacing as well. All right the new cover has arrived now so we can finally push on with this fuel pump rebuild. I'll leave that aside for the moment along with the O-ring that goes with it the little screen and the screw and we'll just keep disassembling the rest of it.

Just here we have another O-ring that I'll remove and then we'll take this midsection off there's even a bit of corrosion on these screw so I'll clean those up as well. Under this cover is a gasket that covers the whole plate so we're replacing that and then if we take this middle part out on the inside here we've got a couple of one-way valves here and here. And on the other side we got the diaphragm that's looking pretty worse for wear. Finally here on the back plate you can see as little part here they call air dome support whatever that means and a spring so we have a new one of these there isn't a new spring so I got to keep that. But the rest of this will just clean up I'll start though by taking this old diaphragm off so we can get to both sides of these little one-way check valve under the diaphragm.

There's a second spring here inside the diaphragm you'll see there's a little cap here that also goes on top of this spring I don't have a replacement for this spring or its little cap so I'll put that somewhere safe. The spring sits here on top of here and this is the side that the cover threads into so we'll keep this safe too. This midsection of the pump looks pretty clean but I'm going to take these old one-way valves out and give it a little of a clean anyway before we put the new ones in. We don't have to be too gentle getting the old ones out obviously just going to pull them out break them the process but that's alright here are the new ones. And we need to push them through to that little bulge in the shaft there is through and pushed all the way in so I can't pull out again. To help with that I'm just going to put a little bit of two-stroke oil on it, when putting them in I'm just going to push it on and push it through from this side.

Hopefully you can see there that the wider section that locks it in has come all the way through so with these always push them in from this side. Don't get the stem in and try and pull the stem out because it's a good chance you'll break it off a bit. On the other one this one goes in from the opposite side you can kinda tell which way they'd go round because if I push this one in from this side it would hit here so I know this one goes this way and then this one goes the opposite side. Alright just gonna wipe the excess oil off. The diaphragm part is actually a diaphragm and a gasket together so you see they're sort of stuck together but they're actually two separate bits we've got replacements of both of these so I'll put that together.

Now I'm going to be building this up now from the back of the pump to the front so from the part that's against the crankcase outwards like this. So next thing is to give this a good cleanup to do that just can use a bit more brake cleaner and with stainless steel brush. There's a little bit of old gasket material here too so just giving a bit of a scrape with the razor blade at a shallow angle to get that off. All right looking better now, next on this back plate goes the spring in this little dome. I've got a new replacement dome so I'm going to put the new dome on to the old spring you'll see in the top here there's a section that the spring goes around a little hole in the center so the spring sits on it and then the domes long enough to go through the spring and for the shaft of that to fit into that little hole so that's how that goes.

After this we need our new diaphragm and gasket and the gasket goes down towards that back plate. Next steps to get the old gasket off this top cover plate, so that's come off pretty cleanly. Rebuilding now from the bottom of the pump up or the inside the engine side to the outside we'll put this spring on here then this little air dome support as they call it goes down into there get that sitting straight then our gasket. Next thing to do is lay the diaphragm on it'll be held up by this spring here that's okay for now once the diaphragm is on I want to lay this section here the spring and the cap so that it's centered in this circular section here. So I'll pop this diaphragm on then we'll take the little cap and put it in the center and then rest the spring on top of that. Now I'm going to do is take this midsection you can see there's a hex section in here and this is where this female thread goes in I can hold this from the back like this by pinching it then I'm going to drop it on so that this little dome here goes with the spring around it.

Next thing on is the new cover plate gasket then the cover plate itself, once that is on and I'm holding in a pressure here just to stop the spring pushing it all up I can put the new O-ring round here which helps hold it. Go a little bit just got a bit of crud on there now just get that off stay in a pop cover on now we can screw these down. Before I get the screws back in what I'm doing is just having a look that I can see all the gasket and diaphragm edges evenly and you can look through all the holes and they're all lined up that way you know the diaphragm your gaskets all that are in line before you lock screws in. The manual doesn't seem to call for it but I think you could probably put a little bit of Loctite on the tips of these screws I don't think it's gonna hurt but I'm just going to snug them up, I don't think they're gonna come undone.

So this is our little O-ring and you O-ring around this center female thread here and screws go here because the bottom two here are the two mounting bolts. All right finally back to our new cover and I'm just gonna push this strainer in so it's reasonably snugly in there and then we have a new O-ring for that as well. To hold this O-ring in place when I tip it upside down I'm just gonna put a really small bit of rubber grease on it you don't want to use a lot because you don't want it sort of inside the pump, it's probably not gonna be the end of the earth. It'll just get washed away by the fuel eventually but just a little bit helps. Now what you need to do is position this top cap so if we lay it on like this you need to position it so the barb comes between both these fasteners so you can get to them although it's slotted for a screwdriver this little top cover bolt also has an knurled outside so you can undo it with your fingers.

The idea there is that it's something you can get to really easily to clean out that filter should it get blocked up. This one last piece that came in the kit we don't need for this particular pump it's for a different style. And the last bit will actually be using is the gasket that goes between the fuel pump and the engine block so let's go pop it back on. Before we put this back on I'll just mention the center hole here is actually what comes in the back of the pump here and this is where the pump gets a crankcase vacuum from so as the motor compresses fuel and air in the crankcase you'll get a high pressure then as the piston comes back up you'll get a low pressure behavior and that's what drives the fuel pump in and out. What's slightly different about these pumps to more modern pumps is normally a modern pump just goes in the crankcase and that's it. In this case however we also have a second hose coming from the bottom cylinder so we sort of get these oscillating pressures to drive it with this dual action. With the new gasket all I'm going to do is hold it on push the bolts through like this that way I have to fiddle around holding the gasket in place while I get it lined up.

There's quite a bit of thickness to this gasket so I think you can sort of put a fair bit of pressure and just squash it down a little bit gaskets don't really work if they're completely crushed but just putting it under a fair bit of pressure I think is good. If you really wanted to I think you could also use a little bit of Loctite on these bolts but dry for now. All right now we're going to reconnect all our hoses we had the crankcase pressure for the top cylinder coming straight into the body of the pump then we have the crankcase pressure for the bottom cylinder coming up here to the back section the middle section of the pump then at the top here we've got the fuel in so I'll connect that one and we know this is our fuel line because we simply trace it all the way around to our fuel Inlet here.

And then finally here the smallest one is the fuel out, the fuel out then forks, one goes directly to the carburetor the other goes directly to the primer solenoid. The last thing I do is just put a cable tie on each one as a bit of a hose clamp. Once I've got them on I like to just grab them close with a pair of pliers and just give the pliers a bit of a twist just to ratchet it up one or two notches tighter. Once that's done just chop them off you can actually get little flush cut pliers specifically for cutting these really close saves you having any sharp edges to cut yourself on they're a nice tool if you can get one. All right and there we go one newly serviced fuel pump ready for action.

There's one final pretty important step when you do any sort of work like this whether it's your fuel pump fuel hoses carburetors whatever and that's to squeeze the primer ball until it's firm and then look for leaks. Obviously fuel leaks are pretty dangerous you don't want a stray spark, heat from the engine or whatever to ignite it so you want to make sure everything's bone-dry after. It's got full pressure and then you're pretty confident to go. Alright well thanks for watching I hope this video helps you if you're looking to service your own fuel pump.

Next video with this motor we'll be getting on and doing more on the lower unit again. Alright well take care I'll catch you later.