older johnson 72?--power loss at prop above 1/4 speed

T

trippled

Recruit
Joined
Jul 4, 2011
Messages
1
It starts and runs fine. when I try to accelerate over around 1/4 speed you feel the motor speed up like normal but it feels like something slips and the prop does not seem to go faster. I took the prop off to see if the sheer pin was broken. it is not. the prop is pin driven and looks ok. any suggestions?
 
lindy46

lindy46

Captain
Joined
Nov 27, 2008
Messages
3,886
Re: older johnson 72?--power loss at prop above 1/4 speed

Spun prop hub. There is a rubber bushing between the hub and the prop which you can't see. It is designed to slip if you hit something. With age, the rubber deteriorates and the prop slips on the hub. You can check to see if that's the problem. Remove the prop and draw a line across the prop and hub with a waterproof marker. Put it back on and run the motor until you duplicate the problem. Take the prop off and see if the line has moved. If so, it's a spun hub. Prop can be re-hubbed for about $45-50.
 
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