Evinrude 4 hp 2 stroke problem. Updated with pics!

[modopopcorn]

Hello everyone!

I have an Evinrude 4 hp 2-strokes that doesn't work as it should, it is from the mid 80's I believe.



The problem is that when the engine is cold, it works pretty good, it accellerate quite ok and it is very easy to start. However, when it starts to get warm, I have to push the choke on and off constantly for the engine to keep running. I have cleaned the carburetor, blown clean nozzles and the sparkplugs look good. I have adjusted all the different ways on the carburetor without it making any difference. My brothers father in-law sometimes tinkering with outboard engines and he thinks it may be a problem with the gasket to the crankcase.

After reading around on various forums, it feels like a likely problem but I would still like to have some more tips and tricks on things that may be worth checking out so I don't tear the engine apart for no reason. It would also be nice if someone would be kind enough to point out exactly which gasket I'm going to check if I will have to tear the engine apart.

Schematichs

 

[F_R]

Re: Evinrude 4 hp 2 stroke problem.

Re: Evinrude 4 hp 2 stroke problem.

If the crankcase is leaking, it will be obvious--you will see fuel coming out the leak. But I seriously doubt that is the problem. I'd rather think you don't have that carb as clean as you think you do? OR you have a fuel pump problem. Will it keep running if you give the squeezer bulb a squeeze? Are you running it on a boat,on the lake, or in a barrel? If in a barrel, you may be asking the fuel pump to lift the fuel too high.

 

[modopopcorn]

Re: Evinrude 4 hp 2 stroke problem.

Re: Evinrude 4 hp 2 stroke problem.

I'm not entirely sure where to look for the leak from the crankcasegasket, sure it's a bit moist and oily, but I find it hard to believe its because of the gasket. When I run it in a barrel it runs smoothly, my neighbor is a bit of a pain in the a** so it isn't possible for me to run it for a long time without disturbing the peace. But it's almost as its no problem at all when I run it in the barrel, and when I hook it up on my boat and start it up, it runs great for the first minutes and after that I have to start using the choke to keep it alive every 10 second. Actually I have never been able to reach top rev. when I go over 50% on the throttle (before it gets warm) it just dies and when I release the throttle it fires up again. It's possible that the carb. still isn't in the best shape, tomorrow I will swap it for a reserve and fire it up in the basement (don't worry, great ventilation ) so my annoying neighbor wont hear it.

My english isn't the best (I'm from Sweden) so I'm not entirely sure what you mean by asking to much from the fuel pump, the enginge has a bulit in gas tank and it falls down straight into the carb if I'm not mistaken, If you could explain a bit further I would appreciate it a lot! =)

Thanks for the tip! =)

 

[nwcove]

Re: Evinrude 4 hp 2 stroke problem.

Re: Evinrude 4 hp 2 stroke problem.

no prob with your english!! better than mine!! sounds like you need to really clean and re-kit the carb. dont cut corners there as it needs to be done regardless of any other issue with the motor just so you can rule it out as the problem.

 

[Robj]

Re: Evinrude 4 hp 2 stroke problem.

Re: Evinrude 4 hp 2 stroke problem.

Definitely sounds like a fuel problem. I would go through the carb. Could also be a faulty fuel pump, but carb is my first guess. I usually run my small motors in a garbage can. Neighbours have never complained, if they come outside, then I just offer them a beer and everything is good.

Whatever you do, don't run it in the basement. It will stink for weeks. I much rather have the neighbours pissed off than my wife.

 

[Rick.]

Re: Evinrude 4 hp 2 stroke problem.

Re: Evinrude 4 hp 2 stroke problem.

Your English is just fine. Your motor won't have a fuel pump as I see the top tank fuel cap others may have missed from your picture. I would agree with others about making certain the carb. is clean. I have a 71 (with a fuel pump) that was giving me a horrible time and would not stay running without the choke being in a perfect spot (almost fully choked) and the throttle in just the right position. I actually had blisters from pulling the starter rope so frequently while trolling. Turned out to be the intake manifold gasket was leaking and the warmer the engine got the more it leaked and the more stubborn it was to keep running. The problem was it just wasn't developing enough draw to pull the appropriate amount of fuel from the carb. Cold it would start well and often run fine for up to an hour before the stalling problems began. In the end it would give me trouble within a few minutes of starting it. Once I replaced the intake gaskets she ran all day without a stall, no choke (after start) and in any throttle position. I assume you are opening the fuel cap vent? Best of luck. Rick.

 

[modopopcorn]

Re: Evinrude 4 hp 2 stroke problem.

Re: Evinrude 4 hp 2 stroke problem.

I've taken apart the carburetor and taken a few photos, the intake manifold gasket isn't looking good.



In the bottom left corner there is a damage to the gasket, and on the engine it looks like this.



There's a lot fluids in the holes beneath the intake holes.

I'm struggling to get the float loose and any tip on how to do it without causing any damage to it would be great!





When I removed the nozzle in the middle of the float the needle that runs through gave a lot of resistance, when I carefully removed it I saw that the needle isn't centered, could this be a problem?



I've also realized the engine isn't from the mid 80's, its from 1978, I've checked the serialnumber and matched it against the schematics, so you can find the correct schematics here.

Update!
The floats brassarm was jammed pretty tight to the pin, I carefully loosened it and now the float moves smoothly up and down. My brother will try to get a gasket for me and I will clean everything thoroughly before assembly and start it up tonight, I will take it to my grandmothers garage, after some arguments with my girlfriend I've come to realize that starting up the engine indoors wouldn't be good for my health (she would beat the crap out of me!)

 

[Rick.]

Re: Evinrude 4 hp 2 stroke problem. Updated with pics!

Well that gasket looks horrible. Never seen one that stained. It looks like rust in the picture but I would change them for sure. If you are able to get a new carb. kit from an omc dealer it would/should come with a new composite float which is recommended over the cork one. The cork can absorb fuel if the shellac coating is broken down. Not concerning (to me) about the tube not being centered in the carb. port. Most I've seen are not centered and work just fine. A sticking float will cause you lots of problems so you must get the float pivoting effortlessly on the pin. If you didn't remove the float and needle you have not cleaned the carb. properly. Your on the right track and I have to say your girlfriend is right. I would never run it in a confined space. Not healthy at all and potentially fatal. Rick.
EDIT: a picture of the reeds would be nice to see.

 

[modopopcorn]

Re: Evinrude 4 hp 2 stroke problem. Updated with pics!

Its ventilated but ofc. its not as good as running it outside, problem is that it is about -25 degrees Celsius outside here in northern Sweden for the next 2 months, but I will head over to my grandmothers garage as soon as I've assembled the engine again. I've cleaned the carb as thoroughly as I possibly can I'ts drying out so I can assemble it tomorrow, I've ordered av new gasket and should have it before next weekend. If I'm lucky I can be out on the lakes in the beginning of may! =)

Pic on the reeds




Carb disassembled (does anyone recognize the logo on the towel? )

 

[nwcove]

Re: Evinrude 4 hp 2 stroke problem. Updated with pics!

MODO.....Forsberg and Naslund came from that club.

are you getting a carb kit for the motor? its a must if you want it to run as it should.

 

[modopopcorn]

Re: Evinrude 4 hp 2 stroke problem. Updated with pics!

Correct! =) I'm living in a suburb just outside ?rnsk?ldsvik where MoDo plays, I've met Nazzy a number of times and he's a living legend in this area!

On topic: There's only 3 dealers in Sweden that sells spare parts to Evinrude engines, problem is that none of them sell the carb kit anymore, it isn't even possible to get my hand on a new float. And if I get my hands on a used one its probably cheaper to buy another used engine and hoping the carburetor is in good shape. Ofc. I can order from USA but the shipment would be like $50, Its a bit expensive so I'm hoping it runs well with the old parts.

 

[Rick.]

Re: Evinrude 4 hp 2 stroke problem. Updated with pics!

You climate is about the same as where I live it sounds like. Your reeds look fine. With the shape of the gasket I thought they might be fouled up but no problem as far as I can see. You say you ordered a gasket. I would have ordered two, one each side of the reed plate. If the cork float is the best you can do you can always re-shellac it to keep it from soaking up fuel. If you can't get a kit try for a new needle valve and seat and new slow speed needle valve packing gaskets.
Rick.

 

[modopopcorn]

Re: Evinrude 4 hp 2 stroke problem. Updated with pics!

There's a rubber gasket on the carbside that looks as good as new, from what I can see on the schematics I only need one new gasket on the engineside in the intake manifold, do you think I should replace the rubber gasket as well?

Just to make sure that I've understood everything correctly.

When the engine is cold it runs ok because everything is cold, nice and tight, when the engine starts to heat up the gasket starts leaking and parts of the fuelmist is leaking down into a hole, because of this I have to work the choke and the fuelmixture and whatever the setup I use it wont make it any better because the leaking gasket will always pass some fuelmist and the engine will blur and die. With a new gasket in place the engine should run smoother (maybe not perfect because of old carburetor parts) and it shouldn't stall all the time.

Have I understood the problem and the possible solution?

And by the way, is there a default setting for the slow speed valve? I screwed it all the way down to the bottom and then loosened it about 2? turns.

 

[the machinist]

Re: Evinrude 4 hp 2 stroke problem. Updated with pics!

You may be able to clean the carb enough to have it function. if you can not get the manifold gasket, find some gasket material & make your own.

As for the reeds, I can not see them because of the stop plates & it looks like there has been some corrosion, so suggest pulling the plates off, check & clean/replace the reeds themselves.

 

[Rick.]

Re: Evinrude 4 hp 2 stroke problem. Updated with pics!

Gaskets 2 and 7 from the schematic you provided are the two I'm speaking of. Gasket 2 is not rubber on mine, both are made of the same material. I'm no expert but I'll try to explain. When the intake gaskets leak, there is a lack of suction to pull a proper amount of fuel from the carb. When the engine is cold, there is enough fuel mix sitting in the bottom to provide a seal but as the engine warms the fuel mix viscosity changes and air gets sucked in where it shouldn't. The more it leaks the less gas comes from the carb. and the more choke you need. Because it isn't getting the fuel needed to run the only way to keep it going is to richen the mix by applying choke(less air). I'm not saying this is your problem, only that it might be, especially after seeing the condition of your gasket. I don't have my book here at home, it's in my heated shop (LOL) but I would set the slow speed needle at 1 1/2 turns to start with. If that is wrong I will let you know. Rick.

 

[modopopcorn]

Re: Evinrude 4 hp 2 stroke problem. Updated with pics!

Well, I'm a bit puzzled, the carb matches a 1978 model, and what I can tell from the serial number it is a 1978, but on all schematics I look at the intake manifold looks a lot different on the 1978 than the one I have look like, maybe its could that the schematics are made for North American engines and maybe the European version isn't identical, but from what I can tell the gasket from a 1979 is identical to the one I have on my engine, so I ordered that one.

I've adjusted the low speed valve to 1 ? turns instead, I guessing it will be a lot of fine tuning before it runs well enough to use for trolling.

Now I'm just hoping to get my package from the part supplier in Stockholm as soon as possible so I can try it out, I will try and make a video of it so you guys can see and hear how its running (If it starts) =)

 

[boobie]

Re: Evinrude 4 hp 2 stroke problem. Updated with pics!

Maybe it's my eye balls but from the pics of the carb, that float isn't upside down, is it ??

 

[modopopcorn]

Re: Evinrude 4 hp 2 stroke problem. Updated with pics!

Well, I havn't flipped and it looks exactly the same on my spare carb, so I think its in order. Also it looks the same on the schematics. =)

 

[nwcove]

Re: Evinrude 4 hp 2 stroke problem. Updated with pics!

Maybe it's my eye balls but from the pics of the carb, that float isn't upside down, is it ??

i dont think its your eyeballs!!! it sure looks upside down to me too.

 

[modopopcorn]

Re: Evinrude 4 hp 2 stroke problem. Updated with pics!

Just took another look on the schematics and as you point out, it could be upside down, would this affect the carb in someway to get to much fuel because the float can move much further down?