Spun hub -- YES or NO??

[grady23]

Itook the Grady out for it's spring ride and evrything ran great -- At first.
After a 25 mile long cruise, we stopped for lunch. As we were leaving, going thru the narrows, I strck something. Wasn't much of a noise and the boat seemed fine. Once we cleared the "No Wake" zone, I put her up on plane and everything was fine for about 30 seconds. Then the starboard engine wnet up in RPM by about 400-500 revs and the performane dropped off. Classic symtom . We should have stopped an check the engine, but I wanted to keep the boat on plane so I increased the revs on the port engine to compensate. After we got back to the dock, I raised both engines and check -- Nothing found. Took the boat back out and everything seemed fine.
I even slowed the boat and using only 1 engine, took off and everything seemed normal. I did this with both engines and everything was the same.
SO -- My big question is -- What the Heck is going on??

 

[Doc Stressor]

Take a colored sharpie pen (the ink in waterproof) and put a mark on the hub across the rubber bushing. The next time you run your boat, check to see if the marked area has moved. It if has, the hub is slipping.

 

[seasick]

Take a colored sharpie pen (the ink in waterproof) and put a mark on the hub across the rubber bushing. The next time you run your boat, check to see if the marked area has moved. It if has, the hub is slipping.

Good sugestion but i suspect the hub spun. It will probably act up again real soon.

 

[BobP]

Did you wrap something around prop and it came off by itself ? Plastic bag, weeds, etc.

Lower unit is either engaged or not.

It's either that or spun = RPMs up and loss of speed.

 

[grady23]

Bob --- That's the weird thing. It was acting up after the lunch break. It had acted just fine even after several stop/starts and getting up on plane.
I acted fine even when I tried to get the boat on plane with just 1 engine. BTW -- It's never been capable of getting completely up on 1 enegine.

 

[Doc Stressor]

I have had spun props that would only slip intermittently with results that were similar to what you have described. It is more common on multi engine boats since the other engine(s) help the bad prop under high load conditions. But they eventually let go completely.

 

[BobP]

Then match mark the hub and prop body as suggetsed if you want to confirm it yourself next time.

 

[Capt Khaos]

Just My $.02

The main man at Frank & Jimmy's prop shop here in Ft. Lauderdale told me the hubs for Mercury props are much better than Yamaha's. Lots less prone to spinning.

 

[ahill]

Could be cavitation caused by picking up some debris