high rpm slow speed

[popeye-sunshine]

I have a 115 hp inline 6 cylinder serial#oa732564 mercury 2 stroke.The problem is boat seems to work quit well until I give it more throatle then the engine screams from rpms being so high and boat does not go any faster.Any thoughts to my problem would be much apperiatied.Thank you

 

[usskydvr]

Re: high rpm slow speed

Either your prop as too low a pitch or you have spun a hub on the prop.

 

[popeye-sunshine]

Re: high rpm slow speed

there's nothing wrong with the prop boat worked fine until sunday.I can spin the prop by hand and feel and hear the drive shaft spin

 

[usskydvr]

Re: high rpm slow speed

Unless the spun hub is REALLY BAD ( I have only seen one in 25+ years) you won't be able to test for a spun by hand. There is still too much friction to tell.

 

[starcraft1982]

Re: high rpm slow speed

yep.if boat used to go alot faster w/same prop as it has now,youve probably got a spun hub.get her fixed and go boating.