15hp prop trouble

[10-7]

fellas, my buddy has 1981 15hp 2 stroke evinrude. he had it out today and said that the motor ran great on plane then he idled it down. Upon increasing rpm's again he said that the motor revved but that the prop while still spinning providing forward motion did not have same revolutions as before. Any ideas, I assume that if shear pin had been broken prop wouldn't spin at all and he didnt contact anything anyway.

I just gave him this motor after it had been sitting in my shed for 5 years. I never had a problem with it like this when i ran it years ago so Im not sure where to start. Any ideas? :shrug:

[bobber_boy]

slip hub???

[10-7]

whats it look like and where located?

[trap50]

The hub is inside the prop. Used to have a shear pin now it's a pressed in rubber hub. If it's slipping the only fix is to send it in and have a new one pressed in. It's right where the splines are.

[10-7]

ill check it out tks

[10-7]

he located trouble it was slip hub tks fellas