MerCruiser Power Problem

[tsal]

Hi all,<br /><br />I have a 1989 4.3 Alpha 1 Mercruiser. It starts OK, and idles OK, but after about 30 minutes, the high speed RPM drops to about 2,500. I can idle down, but when I try to throttle up it coughs and pops out of the exhaust. If I remain at idle for 20 minutes or so, or shut it down for the same amount of time, then my top end is back. Any ideas would be appreciated - I think it's fuel related, my brother feels it is electrical...

 

[BIGALF]

Re: MerCruiser Power Problem

I SEE YOU NEVER GOT AN ANSWER TO THIS PROBLEM. iF YOU GOT IT FIXED i SHURE WOULD LIKE TO KNOW WHAT IT WAS. i SEEM TO BE GETTING THE SAME PROBLEM ON MY 240 SEARAY dECKBOAT WITH THE MERCRUISER EFI.
I THINK I NEED TO CHANGE THE SPARK PLUGS AND KEEP ADDING FUEL INJECTOR CLEANERS

 

[Don S]

Re: MerCruiser Power Problem

Try this test procedure, sounds like you may have a fuel dilivery problem.

http://www.iboats.com/bbboard/bbBoard.cgi?a=viewthread;fid=24;gtid=1107009

BIGALF, please turn off your cap locks, it's hard to read, and in forums it's considered yelling, and I know you aren't yelling at us .............. are you :%
You should also start your own thread, you should include all of YOUR information, including year, make, model number, and serial number if possible of your engine.

 

[imported_rosco]

Re: MerCruiser Power Problem

had a ford mustang with a 302 that did the same thing. cold it ran fine. when it was warmed up, it would loose power. if it set or idled for a while, it would run ok for a whilke again before loosing power.

it also used to backfire through the exhaust system when i was giving it gas.

turned out i had 4 burnt exhaust valves.

do a compression check.