Yamaha 15 gear slippage

[yama15]

My '99 Yamaha 15 short shaft appears to slip after putting it into forward gear and revving up. It still goes forward but with little speed for a lot of revs. I took the bottom casing apart with no visible sign of damage/wear to the clutch dogs or gears and a little wear on the prop shaft where the clutch dog slides onto the shaft splines. But I feel sure that this is not the problem. Could the slippage come from the engine side of the drive shaft?
Any other ideas? Oviously this model does not have a shear pin.
Thanks for any suggestions.

[jb123]

not very familiar with the smaller motors, but my 2 cents, if it is in gear there should be no slipping. what prop do you use, does it have a rubber hub, as this is where you could get slippage as you describe.

[yama15]

Thanks, after posting this a friend mentioned the possibilty of the rubber hub failing. Will check it out this morning. Thanks for your time.