1975 20hp merc bogging and wanting to die on top end

[MRJ82]

The motor runs great until it gets to the top end and then starts bogging and wants to die. I have replaced the gas tank, all fittings, "all" fuel lines, primmer bulb, and rebuilt the fuel pump. But the problem still persists. Does anyone have any other ideas? I'm about at my wits end with it

 

[Mtbiker9000]

Re: 1975 20hp merc bogging and wanting to die on top end

does it only happen when the motor gets warm, or does it do it right away cold, does your motor have points, if so I had an outboard once that when it got warm the condenser would get screwed up, replaced it and it never happened again.....just a thought.

 

[MRJ82]

Re: 1975 20hp merc bogging and wanting to die on top end

Thanks for the suggestion, but this model does not use points. It Doesn't matter if it is cold or has been warmed up. runs great up to top end and will even stay there for a few seconds, and then starts bogging and wants to die. I have to drop rpm almost to idle so the motor can catch back up to itself and start running good again.

 

[MRJ82]

Re: 1975 20hp merc bogging and wanting to die on top end

any other thoughts?

 

[mercuryman25]

Re: 1975 20hp merc bogging and wanting to die on top end

high speed jet in carb! clean it really good with a airhose and gumout carb cleaner!!