15hp yammy problem

[bear_au46]

hi all new member with a problem
04 15 yammy starts and runs ok motorwise
initial acceleration ok
when on plane (any speed) just travelling along under normal
load the motor will suddenly over rev and boat loses propulsion.
then change to neutral re-engage gear and its ok again for a minute
or so then reoccurs
initially thought rubber bushing in prop might be u/s , but I thought
that if that were so the the prop would be more likely to do that when accelerating
any suggestions or theories appreciated
trevor

 

[cousinabe]

Re: 15hp yammy problem

you spun the hub.
did you ever hit anything?

http://forums.iboats.com/showthread.php?t=137447

 

[bear_au46]

Re: 15hp yammy problem

have run aground on sand before never hit anything have put into gear and tried to turn prop but everything seems ok there
have never hit rocks or driftwood etc.

 

[cousinabe]

Re: 15hp yammy problem

"Spun in the prop" means that torque from the engine causes the rubber spline between the prop shaft and the prop to slip inside the prop hub. Thus rpms climb high, but the prop doesn't turn faster. Best analogy is to compare it to a car tire. When you floor it and the tire breaks loose, the tire spins, the speedometer climbs, but the car doesn't move. When you back off, it catches and it works fine again.Hope this helps.

Sounds like it is disengaging when the rpms gets high enough. try a new prop.

read this entire post:
http://forums.iboats.com/showthread.php?t=137447