yamaha 90 Hp gear problem

C

chompin

Recruit
Joined
Oct 25, 2011
Messages
2
The engine went into reverse and forward without a problem
and allso i haveNo problem at low speed
but whan i am Trying to increase speed engine seemed struggling regardless to propeller rounds
i checkd the prop and looks good
could it be gear problem i do not hear noises or other signs from lowr unit


Thanks
 
R

robert graham

Admiral
Joined
Apr 16, 2009
Messages
6,908
Re: yamaha 90 Hp gear problem

It sounds like you may have a "spun hub"...the prop is made in 2 parts, the outer with the blades and the inner with the splines. They are held together with a black rubber hub bushing that can fail(like a warn out clutch), causing your outer hub to slip when you apply power. You can mark the inner and outer parts with a magic marker, run the motor, then check if marks are still aligned...if not, then a propeller shop can repair the black rubber bushing or you can buy a new prop. Good Luck!:)
 
9

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
8,874
Re: yamaha 90 Hp gear problem

If you are saying RPMs do not increase as they should when throttled up then you have a motor problem, most likely fuel related (carbs maybe) or loosing spark on a cylinder
 
C

chompin

Recruit
Joined
Oct 25, 2011
Messages
2
Re: yamaha 90 Hp gear problem

Thanks robert
Thenks yam99

Dear Robert

I suspected the rubber and he looked a little worn
So I tried to put the engine in gear and rotate the propeller by hand force and he does not move
Can I nevertheless still suspect propeller ???
 
R

robert graham

Admiral
Joined
Apr 16, 2009
Messages
6,908
Re: yamaha 90 Hp gear problem

If the hub is spun it is quite possible that the rubber bushing will still be too tight to turn by hand, so mark it and run the motor to see if it's slipping. Good Luck!
 
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