2007 50hp mercury rpm problem

[slab seeker]

Have a brand new mercury 50hp 2cycle oil injected outboard. Having problems with rpms. Runs good as long as you keep at are under 4500rpms when i hammer down on it and pass 45oorpms motor winds out and boat goes no wheres? checked foot all good motor trimed all the way down and tried adjusting no luck. Once back to 4500 rpms are lower it runs ok.

any info would be gladly apreciated.

 

[Silvertip]

Re: 2007 50hp mercury rpm problem

Sounds like the prop begins to blow out (ventilate) at higher rpm. Where is the antiventilation plate in relation to the bottom of the boat? In other words, is the engine mounted too high. What prop are you using and what boat is this engine installed on?

 

[slab seeker]

Re: 2007 50hp mercury rpm problem

This engine is on a 20' party barge. As the engine it is mounted as low as possible on transom. as for as the prop not sure, its a brand new boat baught in february.