RPM drop and no power

[GuinnessGuy74]

I just rebuilt my Mercruiser (GM 350). The boat runs fine for about 10 mins. Doing a cool 25 kts at about 3500 RPM(about 3/4 throttle). After about 10 mins, the RPMs drop to about 2500 and any increase in throttle just barely makes 3000 and sounds like the engine is bogged down. The motor then runs slightly hotter than normal. After sitting, the boat will run fine again, but then same problem occurs. Changed the fuel filter, and added some fuel stabilizer....no change. Coil, plugs, points, condenser, cap and rotor are all brand new. Any thoughts as to the problem? I don't think it is timing cuz when it runs, it runs great, and I think timing would affect it always, no? Thanks for all the help......<br /><br />Jim<br />Long Island, NY

 

[tommays]

Re: RPM drop and no power

i can only guess but do you have a fuel water sepator the carb filter will clog in no time if it is the only filter before i added the water sepator filter my carb filter would clog up so bad the engine go lean and the temp would start to rise from 150 to 175 deg <br /><br />tommays

 

[Bondo]

Re: RPM drop and no power

I'd be looking very closely at your Fuel Delivery.........<br />Could be Anything from the Tank, to the Carb.......