engine loses power

[Don Howard]

I have a 90HP Mariner engine built in 1989. After running fine for 15 or 20 minutes the engine loses power although the throttle is all the way open. I have new fuel tanks and hoses and have checked that the vent on the fuel tank is open. Any Ideas?

 

[Bondo]

Re: engine loses power

Ayuh,... Welcome Aboard,...

Sounds like it's goin' Lean...

Probably oughta rebuild the carbs...

 

[wellsc1]

Re: engine loses power

Maybe consider the fuel pump too. I forget how high, but it's a high percentage of time that the fuel system is usually the culprit. Have you replaced the fuel filter in case is has a partial restriction?

 

[Don Howard]

Re: engine loses power

I will change the fuel filter but why would the engine lose all its power and run at an idle after running fine for 15 or 20 minutes. Another thing I did not mention is this problem happens after I slow down (under a bridge) and then try to go fast again. If I let the engine sit for awhile and restart it work fine until the engine gets hot again?

 

[SaabFAN]

Re: engine loses power

I had the exact problem with my outboard-engine 2 weeks ago, after cruising for ca. 10 to 15 minutes at 40% throttle while planing. After slowing down and accelerating again, the engine sputtered, then stopped and only started with the choke pulled.
Solved it by re-adjusting the idle twice.
Seems to me, like something had clogged the fuel-jet inside the idle-circuit of the carb that came loose because of the fuel-system cleaner i mixed into the fuel at that weekend.

 

[Don Howard]

Re: engine loses power

problem solved. There was dirt in the carburator and the fuel jet was getting clogged. Cleaned the carburator.

Thanks for your help.