Robin 422 engine surging

[MuncyBob]

As soon as it warms up a bit I'll "get under the hood", but thought I would ask this first to possibly save some time. The 422 starts up fine but the engine "surges". It will stall at min throttle even when the engine is hot. I can run it and get a job done but you can hear the surging.

Is this possibly something as simple as the fuel filter? I'm hoping it's a simple fix as I have absolutely no carb. experience.

 

[BobRip]

I just had my Honda driven generator surge. I was told by the manufacturer that it was probably the float needle valve. They recommended fuel injector cleaner. I put some in the fuel tank and it did not fix it immediately or after many minutes of running. I then pulled the fuel bowl and cleaned the inside with carb cleaner. I pulled the needle and cleaned that. I ran it today for two hours and it ran fine after a few minutes of warmup. Try the fuel injector cleaner and run it for awhile. I have not had this problem with the Robin 422.

 

[Gravy]

Surging is typically a symptom of a lean condition. Replacing the fuel filter can't hurt, but it's more likely that a carburetor jet is partly obstructed.

Does it run better if you close the choke partway? If so, that confirms a clogged jet. If that's the case, you can run it at part-choke to get by until you can get it fixed right.

 

[BobRip]

Surging is typically a symptom of a lean condition. Replacing the fuel filter can't hurt, but it's more likely that a carburetor jet is partly obstructed.

Does it run better if you close the choke partway? If so, that confirms a clogged jet. If that's the case, you can run it at part-choke to get by until you can get it fixed right.

The part choke helped my generator. It is a lean condition.

 

[MuncyBob]

Thanks!! I will be looking at the carb today and hopefully take her out for some work if it doesn't snow(can't let her get wet!!).

 

[ponytug]

Don't forget that the gasoline in the combustion mixtures plays an important cooling effect in an air cooled engine. Running lean tends to over heat the engine and exhaust valve/headers.

Try the fuel cleaner-it can't hurt, but be prepared for taking the carb out and cleaning it.

If your fuel hangs around for awhile, you might want to get in the habit of adding a fuel stabilizer to reduce the gumming tendency of old gasoline. "Old" being more than a month old. Unless it is peak chain saw season, pretty much all of the gas coming on to the property gets dosed with fuel stabilizer.

All the best,

Peter

 

[stray]

Mine has done this several times. It is agervating an't it. Take the jet out of the bottom of the carb, blow it out and it should take care of this. O yes, take something and pinch the gas line off before you do this. then only a little gas will spill out.

 

[MuncyBob]

Appears it's carb cleaning time as the injector cleaning fluid did not do the trick. Are there gaskets that may need to be replaced when reinstalling the carb? Anything I should or should not do?? This will be my first carb removal off of anything.

 

[Gravy]

I have had my carb off and apart a couple of times without gasket damage. Just be gentle with it and you should be OK.

 

[stray]

All you may need to do is unscrew a little thing on the bottom (maby on the side, can't remember for sure) that looks like a bolt. take it out, blow it out with an air hose and put it back in. sometimes you won't even see what was in it but each time i have done this it has taken care of the surge problem. I had no need to take the carb off.