Engine looses Power on high RPMs

[diver163]

I recently bought this boat and the engine (Mercruiser MCM-260) starts right up and runs great on low RPMs. Whenever I goto high RPMs, after few minutes the engine starts stalling and start loosing power. It immediately runs ok if I pull the throtle down a little. Any idea what is causing it?

 

[Haut Medoc]

Re: Engine looses Power on high RPMs

Welcome to iboats.....
Have you changed the water separating fuel filter?.....
This sounds like a fuel delivery issue.....​

 

[Sorrento 25]

Re: Engine looses Power on high RPMs

My boat was doing the same thing and I found the little screen in the tank pickup tube was clogging with debris from the tank. Remove the pickup from the tank and replace that screen with a mesh sock, or remove it altogether and replace a larger external filter often.

 

[jfl1959]

Re: Engine looses Power on high RPMs

Hello, good luck with the new boat.

There are quite a few things that can cause this problem. Don S has posted a flow chart of causes of low rpm at WOT. Check a few posts over the last few days and locate it.

I had a similar problem and my fix was a very dirty and clogged flame arrestor. I could not believe it. A good cleaning with a can of carb cleaner solved my problem. It was number four or five on the list.

Good luck
Jim

 

[yoeman]

Re: Engine looses Power on high RPMs

try removing the small fuel filter in the carb were the fuel line goes into the carb If it is not plastic toss it and buy a marine filter Ive seen thousands spent on other items before this was discovered

 

[diver163]

Re: Engine looses Power on high RPMs

Thanks you all. You have given me a good list of items to work on. I have cleaned the air intake on Carb including cleaning of flame assestor with 'deep creep' from napa. I did find a bent fule line which I replace with the rubber fuel hose. Not that I want my boat to suck more fule util it's back to 1.99cent per gallon.
I will take it out again in next few days to see if these small repairs have done the job. I guess I have to learn these things along with working on my skills to dock without bumping into my neighbour's boat Thanks again.

 

[bomar76]

Re: Engine looses Power on high RPMs

Get the rubber fuel line off....from pump to carb has to be steel....rubber is neither safe nor legal.