Mercruiser 140 falls off WOT

[boozer1966]

1984 Regal Medallion 175, Mercruiser 140, 2 bbl. Mercarb. Boat was brought back to life after sitting for a couple of years. Replaced entire fuel system with the exception of the tank. Rebuilt carb. Replaced points, plugs, rotor and cap. Set timing. When first launched, engine will run up to 4,400 at WOT for about 15-20 seconds, then slowly drops to about 3,500 and stays there the rest of the day, but runs roughs at that rpm. If you back off the throttle to about 3,000, the engine seems to run fine, but if you try to go WOT, it just falls flat and won't go back above 3,500 and acts like its suffocating. Any ideas?

 

[cr2k]

Re: Mercruiser 140 falls off WOT

Either bad fuel pump or crap in the carb and or filter.

 

[boozer1966]

Re: Mercruiser 140 falls off WOT

Brand new fuel pump and filter. Fresh carb rebuild. Boat runs great up to 3,000 rpm then just falls off. Don't think its fuel related. Ignition? Distributor?

 

[Rjovi]

Re: Mercruiser 140 falls off WOT

Sticking lifter? I had almost the same issue with my motor after I rebuilt it, had a new intake lifter sticking.