please help evinrude 120 problems

[slim433]

I have a 1985 120 hp v4 evinrude that is getting me trouble. We take it out and it runs great for maybe 30 mins then it starts to labor pretty hard rpms up and down and it will die if I don't throttle it back. If I keep the throttle set back to 1/2 it will run like that for a good while. The compression is good and I sync the carbs . If you push the choke it doesn't seem to help or hurt it , the primer bulb stays hard and pumping it didn't help. The pee stream is good and cool to bath tube warm and I can hold my hand on the heads after it dies. The new fuel filter I installed is see thru and it has dirt in it but not cloged shut. Any info you could give me would be great . Thanks mike

 

[Daviet]

Re: please help evinrude 120 problems

It sounds like you are running out of fuel. You say pumping the primer bulb doesn't help so your fuel pump should be ok. If you see dirt in the filter, replace it, it might be restricting the fuel flow just enough to cause a high speed problem.
You migt have some trash floating around in the carbs and restricting a high speed jet, remove the jets and check them. While you have the jets out pump the primer bulb and flush out the carbs.

 

[slim433]

Re: please help evinrude 120 problems

thanks i also bought a fuel water seperater to install . i think i am going to pump all the fuel out thru a filter to make sure the tank doesn't have alot of junk in it as it was sitting for 2 years and is 23 years old. i was thinking it was all fuel but i wasn't sure with the choke and bulb not changing it . thank you very much for your help .

mike