1965 Evinrude Starflight 75hp outdrive issues

[chasejones]

I was tooling down the river this afternoon and all of a sudden the motor revved up. I backed off on the throttle and after that I can only get about a 1/4 throttle of power out of the prop before the motor reeves up again. I pulled the prop when I got home and the pin was ok so I am sure its not that. Been working on this thing for a few weeks now carbs and fuel pump. I get it running really good and now this. I have to say this is frustrating.
Can someone please help?

[Willyclay]

Welcome to the iboats.com forum. The experts here, which I am not, can help you with any question about your boat, motor and trailer. BTDT with a 1962 Johnson 75. My problem was a failed prop hub that allowed the prop to slip which is what it is designed to do. The old ones usually fail because the rubber clutch has deteriorated. You can verify this by making a Sharpie mark on the prop in line with the drive pin holes in the hub. After a trip to the river, check the alignment of the marks. If they have changed, then your hub is bad. The good news is it can be re-hubbed by a prop shop for a reasonable price. FYI, any used prop you may be able to find is subject to the same "old age problem". Good luck!