I’m having an issue with a 1956 12 hp Sea King.
Quik backstory. I fixed this motor up last spring. All was good. Ran it a lot. Real happy with it. I was running it in the Sante Fe and hit something. Twice. Limped back to the ramp after shearing the second shear pin. The next weekend I took it out again. With a new shear pin of course. Idled up the canal to Cross Creek. Ambled up the creek. Idled great. I got to the big lake and opened it up. The boat, a 14′ aluminum wolverine almost got up on plane before the motor revved and the boat slowed drastically. It would only work properly at idle speed. We had fun anyway because I’ve finally lost my fear of the catastrophic failure, mushroom clouds, and drowning.
I was told that probably the prop was spun. I had assumed this so didn’t check anything else, like for example, check to see if it was coming out of forward gear at more than idle speed. I sent it away to be repaired.
But, I just learned, it may not be the prop. In case it matters, the prop is a 9×9. But i’m not sure that’s the way to write that it’s a 9″ prop with a pitch of 9.
At this point, assuming the prop is still actually good, where would one start in diagnosing the issue?
Could it be anything worse than slipping out of gear?
Thanks for any input,
Geer