Drop off in RPMs

[leetbeef9999]

The boat is a 1986 Chris Craft with a 350 HP 5.7 L OMC Cobra (4 Barrel Rochester carb). The boat will hit 4000 RPM, and then the rpms fall down to around 3500. Any ideas? We've tried smaller pitches, and we're at a 13 inch pitch, so that is not an option. Prop is a 15 inch diameter x 13 inch pitch.

 

[cobra 3.0]

Re: Drop off in RPMs

How big is your Chriscraft?

 

[leetbeef9999]

Re: Drop off in RPMs

26 1/2 feet

 

[tommays]

Re: Drop off in RPMs

have you done any fuel filter changes this year it sounds like it is not getting enough fuel <br /><br />the small in carb filter will clog and only pass enough fuel for low speed<br /><br />tommays