'77 erude 85 slowly loses power and dies

[DaMoos]

My '77 erude 85 horse starts right up, idles well, roars down the lake for maybe 15 seconds, after which it slowly loses power and dies. It then takes awhile before it will start again, and even longer before it will start and run well again, after which it does the same routine.

Its not the vent cap, I checked.

When I pull the fuel hose off the pump, gas pours out of the hose. The screen on the fuel pump is clean.

This really feels like a fuel problem to me. It is a very smooth, non-stuttering loss of power untill it finally dies.

Crab rebuild time? I did order the kit.

As a side note, I have a bad rectifier. The part is in the mail. I can't see how that is relevant, but maybe whatever killed the rectifier is causing this too. The smoothness whith which it slowly loses power doesn't make me think electrical, but I am surely a novice here.

Any thoughts?

 

[Daviet]

Re: '77 erude 85 slowly loses power and dies

Try pumping the primer bulb constantly (bypasses fuel pump) and see if it helps.

 

[levi_tsk]

Re: '77 erude 85 slowly loses power and dies

Try pumping the primer bulb constantly (bypasses fuel pump) and see if it helps.

what he said

 

[DaMoos]

Re: '77 erude 85 slowly loses power and dies

If the pump is bad, why would it idle so well, and run well at first? Or am I running purely on what I primed in at start? If this works, is it a bad pump? It idles well on the muffs. Are you figuring that when I open'r up, the higher fuel demand is exposing the possibly badd pump? I'll see if it dies on the muffs, and if priming it as it loses power helps.

 

[Daviet]

Re: '77 erude 85 slowly loses power and dies

Becareful running on muffs, shouldn't run higher than about 1500 rpm, or you might get a runaway.
Your best bet is to back it in the water, you can leave it on the trailer, and run it under load (in gear).

 

[levi_tsk]

Re: '77 erude 85 slowly loses power and dies

Becareful running on muffs, shouldn't run higher than about 1500 rpm, or you might get a runaway.
Your best bet is to back it in the water, you can leave it on the trailer, and run it under load (in gear).

what he said again AND you can have a "weak " diaphram in the pump that will only show itself under load and at WOT when the engine needs the most fuel

 

[DaMoos]

Re: '77 erude 85 slowly loses power and dies

ok, I pulled the head on one side after compression tested lousy. Water definately getting into #3.

Would a blown gasket fit with the other troubles, or is an additional woe?

 

[Sixmark]

Re: '77 erude 85 slowly loses power and dies

Let me guess, it would roar across the lake and then start to lose power and make a light ticking sound just before it died?