Pontoon Boat & Deck Boat Forum

Late last fall I hit a rock, bent up the prop pretty bad, not much damage to the skeg but there is some. Bought new prop for Michigan Wheel and installed it. Its been a crazy spring so last week was my first trip on the lake since last fall.
I now have a vibration in the lower end. Being that the prop is new I don't think its the prop but of course nothing is perfect so that may be the case, i am more concerned that it may be the prop shaft.

My question is how much of a job is it to replace the shaft And any suggestions on figuring out where the vibration really is coming from because i am speculating at best.

Thanks

Were you running aluminum or stainless? If aluminum shaft should be ok but possible.

Aluminium

A prop guard would have saved that prop

http://www.propguardmarine.com/how.html

I dont know what the tolerance on a prop shaft is but it dosnt take a lot to get one out of round and its a major job to change one out.

HERB, i dont want to rob this post so ill start a new one about prop gaurds you might be able to help with.

It either has to be due to a bent skeg, or your shaft is slightly bent. If it's bent it's only a matter of time before the shaft seals will wear and drive oil will begin to leak out. Best to take the lower off and take it in for evaluation.

I agree that you'll want to get it into a shop and have them check the shaft for straightness. For a qualified marine mechanic, replacing a prop shaft is no big deal. For me, it'd be a pain in the rear. The part has a list price of about $241.95, but can be bought through IBoats.com for $204. You'd also want to install new seals if you're taking the lower unit apart.

Skegs can get bent a little and it won't affect the performance at all. Sometimes you might have to adjust the trim tab to get the boat running straight. If they won't bend back, skegs can be cut off with a angle grinder and replaced with a stainless steel skeg for about $100.

Yep, most likely a bent prop shaft. If you have marine insurance they will pay the bill, less deductible.

Thanks everyone. I'll take it down to a Mechanic shop.

You can check the prop shaft by spinning the prop manually. Look to see if there is any wobble where the prop nut is. You can also remove the prop and make a jig to attach to the foot with a straight edge resting on the shaft, spin the shaft manually and see if the shaft deflects from the jig straight edge.

I would recommend letting a qualified service center perform the repair as it can be severe PIA.

This happened to me 2 years ago with an aluminum prop. I hit a rock on the side, not over the top which didnt even put a mark on the skeg. Chewed the prop up badly. The shaft was bent. Parts and labor was $850. Put the motor in gear at idle at trim the prop out of the water for just a second. It will be obvious if the shaft is bent even a little.