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Prop Spun Off Hub, as in GONE

QTwo

New member
I originally posted this in another fuel issue thread I had started, but probably a better idea to post it here in the Propeller section. I have an older Boston Whaler with a 1986 Johnson 90 HP.

This years boating story started with me raising the motor up a few mounting holes on the transom and getting a new stainless steel prop as I was looking for a better hole shot and higher top end. In addition, a new tach was installed and I downloaded a speedo app to see the results. Then purchased an OMC SST 13 x 17 stainless prop off EBay that was listed as nearly new. Appeared to be in great shape in the pictures and looked great when I received. Fast forward - Left the current prop on while I was trying to figure out the fueling issue that turned into the spark wire issue. Finally got the parts and problem figured out last week and all was back to normal.

This past Saturday morning, took the boat out on the lake for some testing runs with the current prop. Changed up to the new prop and went out for a warm up run to make sure all was well with the new prop. Smooth operation, no issues and went back in. The expensive problem occurred when I went back out later to do some testing. Just as I was coming up to mid-range speed, the boat lost all thrust slamming me forward, the engine raced to a high rev and I yanked back the throttle. Raised the motor up and all I saw was a rubber hub, castle nut and cotter pin, intact - WTF! The propeller had spun off and was now swimming with the fishes 50 feet down. No slipping, no tell tales, just gone.

Anyone ever heard of this? I have found info on spun hubs, but that is the splines breaking loose and the prop just spinning on the shaft, not being lost for good. Any ideas? Move this to a separate thread?
 
#Was the washer installed in front of the nut ?-----So the propeller was pushing forward..----Only way it could come off is if it split / cracked.
 
Can happen. Having a spare on board always good. Not sure if there is any way to get some of your money back, but I would try.
 
Is there ANY possibility that the prop hit something? Check for a bent prop shaft. Could have been a suspended, submerged object. Tore prop right off the hub.
 
Correct -----Now that I read post #1 again and the operator being " slammed forward " it might indicate impact with a submerged obstacle.
 
Didnt hit anything. The slamming forward was due to being prepared for acceleration momentum while standing (Whaler with a console) and losing propulsion with the boat decelerating, all unexpectedly. Falling forward would be a better description, thankfully right next to the throttle so I could immediately pull it back to avoid overrevs. After getting towed back in, I checked the skeg and no issues and the hub was still sitting there with the nut and cotter pin in place. I took off the remaining hub, put the old prop back on and went out for a sunset cruise with no issues or vibrations.
 
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