View Full Version : bent prop possibly more question

10-24-2011, 12:06 PM
I just purchased a 03 mobius, I noticed the bent prop when I was looking at the boat, but didnt think to drop it in gear before I purchased it. I got home, had it running for a couple seconds in the garage dropped it in drive and heard a terrible squeeling noise. I shut it down and did some more looking. I cannot turn the shaft by hand with the motor off and tranny in neutral, I would think I could. From behind the boat the lower strut is offset to the left, is it supposed to be? Also the shaft appears to be against the left side of the strut housing,not sitting in the middle of the housing. I can tell I need to have the prop either replaced or repaired, should I assume the strut is bent or made like that? How hard is it to remove the shaft and lower strut?

10-24-2011, 12:12 PM
The strut is offset so that when you go to replace that bent shat, you can sneak it by the rudder.

You can first try and realign the shaft thru the strut, but since you have prop damage and can turn it by hand, I might guess that the shaft is also damaged. Use the search function to find some threads on where to buy a replacement and how to replace the shaft. I watched kaneboats do this in my driveway this past July. It was a hot day and the driveway is gravel, so I think it ended up being a 6 beer job.

One thing we did based on advice from 11 Outback V was to run the engine for a sec with the prop off and eyeballing the shaft which easily let us see the "wiggle" to indicate it was bent.

Good luck, it's an easier repair than it sounds. Order a new prop, have the current one repaired and keep as a spare. Post up some pics of your new toy.

10-24-2011, 12:15 PM
Got my new shaft from Elberts right here (call him he's a great guy and very helpful-- shipped mine same day):


10-25-2011, 02:48 PM
From your description I'd guess the shaft is bent but ....

You can get a pretty good idea if the shaft is bent without removing the shaft by using a dial indicator 12622. Basically, position the plunger on the shaft with the indicator held against a hard surface (e.g., hold it in place on top of stacked blocks on the driveway) - rotate the shaft (yes, it is required that the shaft be movable and with the engine in neutral you should be able to rotate the shaft) - if you get noticable deflection of the pointer on the indicator as the shaft rotates then the shaft is bent.

A better way to do it is to remove the shaft and put it on a lathe to test

I had 2 bent shafts on my cruiser when I bought it - VERY careful eyeballing during an out of water inpection by me and by the surveyor including hand rotation of both shafts did not indicate the shaft was bent but later putting it on a lathe showed clearly that it was bent - I did not have a dial indicator when I did the initial test.

Bent props are very common but replacing or repairing them is essential. Bent shafts are less common and repair or replacement is critical (I have heard that shafts can be repaired but never have found a place that would do it). I have never known anyone who bent a strut but I'd guess that on some of the grounded boats I've seen that the strut was bent and I'd guess that one would absolutely not want to run a boat even briefly with a bent strut.

While we are on this subject, if anyone has replaced a shaft, please post the price you paid for a new shaft. I think they were $500 each for my cruiser but they were 1.75" in diameter and 6' long stainless steel.

10-25-2011, 09:26 PM
I bent my strut, shaft, and tweaked the propeller with 8 hrs on my boat.

I live close to Elbert's shop and he straightened my shaft. He went though a time consuming process of checking the shaft for bent location and using a press to bend the shaft back into tolerances.

There is a local marine running gear repair shop near me that repairs both struts and props. There should be someone near you as well (hopefully).

10-26-2011, 01:30 PM
The terrible squeeling noise is most likely from the strut bushings. Spray some silicone lube on the shaft/strut location and you should then be able to turn the shaft /prop by hand.
To check the shaft follow the alignment procedure to see if it is bent. It is the proper thing to do. Its much more simpler on a DDrive vs a VDrive Read the procedure and get a feel for how everything should be in your mind. Its not rocket science.
If its off to one side at the back of the strut , how is it positioned at the front of the strut? Is it exiting the hull in the middle of the opening or way offset.
On a 03 the motor mounts are 7 yrs old and the alignment should be checked.