Spun prop x2?

Dave Diefenderfer

Dave Diefenderfer

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Hoping there might be some experience here to share.... hunting partner's boat, 16ft aluminum semiV john, with a 25hp honda. We hunted this boat hard last season, with a similar (heavy load, decoys, 3 hunters, gear) with no issues. This year we are motoring through a bunch of shade apparently, they are jumping all around. We are hitting them with the boat and motor, you can feel it! A week ago, the prop spun. Order and received a new prop, spun it on the second day out. In both cases it was hitting fish we are pretty sure. No dings, scratches in the prop. If he comes up to speed real slow, he can keep it from spinning, at least for now...I am suspect the more times it spins, that at some point there will be no return?

So, does this sound like just bad luck? Can you put too high a load on the prop and cause it to spin? Might the thrust washer be suspect, and not the prop? Or both? Will a better quality prop make a difference? What is different between a $80 prop and a $150 prop?
 
Have you tested your old prop to see if it is actually spinning? Take prop off and use a punch to make a mark on the prop and on the hub. Then run the prop normally and see if the marks are still aligned. I bought a Propco prop and thought it was spun only to find out that it was sucking air and had to lower the motor. I will only buy props made specifically for my motor brand. They fit the spindle and the hub sets right without those plastic bushings. I don't think the bushing protect as well from debris getting wrapped around the shaft which can cut the seal for the lower unit.
 
Most likly the diffrence in price bewteen props are aluminum (cheep) and stainless steel (pricey) if the hub is actully spun it may be cost effective to go to a prop shop and have a new hub installed or see if they have a replaceable hub not a press in for a quick fix every time
 
Supplier has admitted that he has seen issues with this prop and without hesitation offered a refund. Buddy ordered a higher priced (replaceable hub, style prop). But in discussions with the supplier, it got us thinking.... during the off-season, buddy installed pods on his hull. Did not make any changes to the attitude of the outboard.... maybe this is cavitation? He will mark the prop and see if he can create issue today or tomorrow... new prop should be here Friday.
 
The difference was one inch in the depth of the shaft. I experience the same issue you described with the aftermarket prop, and the evinrude props would blow out in sharp corners. Now I have no issues other than driving narrow ditches way to fast and running up on banks, but that's not a prop issue
 
Shawn, I know you like to use and abuse your boat and justify it as product testing for Duck Boss Boats. Just keep in mind it's a boat not an amphibious vehicle. Enjoy.


Tom
 
This would be a good time to bring up the difference between cavitation and ventilation. They are confused often and really have two different causes, cures and symptoms. First ventilation is caused by the prop biting air not water. Symptom would be over reving and loss of speed. Most of the time this shows up cornering but can be caused by overtrimming or mounting too high. Most of the time it will show up on the prop as paint looking burnt on the leading edge of the prop. Cavitation is more commonly caused by nicks or burrs on the leading edge of the prop. What happens is the water flow over the prop is disturbed causing the water to boil and the explosion of the bubbles will pit the prop making it look pitted almost like corrosion. Kind of an over simplification but you get the idea, know what the cause is and then it is easy to fix.
 
Now Tom pushing a fine water craft to the edge of it's ability is not abuse it is just what duck hunters do. I have had the old gal for 13 years now and would never like to think that any of the hard stops or ice breaking as abuse, just taking a trusted friend for a ride. Just as I don't see asking my young lab to jump into ice filling salt water to get my ducks or exposing my benelli to salt spray and watching it rust before my eyes. Waterfowlers are a tough bunch and there gear has to be up to the task. That's why when we find something we like it is hard to get us to change, unless the new improved product is of equal quality or better.

My with motor set up where all caused from ventilation. The prop was just a little to high and would suck air from the surface.
 
Unless defective, prop shouldn't spin from hitting a few shad. You might want to lower the motor a notch, sounds like the prop is losing bite.
 
I know that the larger Hondas (90 HP) have a hard rubber type hub that sits inside the prop and around the shaft. There's a possibility that the hub is worn and that the prop shaft, and not the prop itself, is spinning.
 
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