spun hub

[rockyman]

1981 galaxy 19.5 ft. 165 hp mercruiser outdrive 165hp inline 6cly 1978 model .i changed from 19pitch prop to 21pitch . i went up 2 pitches and down 1inch in diameter, launched boat throttled up to about 3000 rpms not plained out yet and all of a sudden i felt bad vibration and rpms went up greatly,lower unit was trimed all the way down , could this be a spun prop.

 

[JerrfyLube]

Re: spun hub

Possibly...a spun hub feels sort of like a badly slipping clutch. It will work fine to a point, then HP will overcome it and will spin the hub. Its usually a pretty smooth movement so if you werent feeling any large clunks, bangs or other obvious signs, its most likely a spun hub.

The rubber bushing in the props shrink with age and will let it spin...is this an older prop?

 

[rockyman]

Re: spun hub

yes it was a used prop and an older one at that . thanks , i have not experience like that before .