View Full Version : How to change a prop???

07-11-2007, 03:18 PM
I lifted my boat out of ther water the other day and noticed a couple of tiny dings in my prop (the engine / shaft were not vibrating in any way). So I thought I will get a new one and have the old one reconditioned so I had a spare.

I went to the marina to get a new one and they one had a reconditioned one in stock to I thought that will do and I will send my original one off to be balanced etc.

I fitted the new prop and the went out on the lake and the boat nearly shook its self to pieces. I took the new prop back to the marina and they told me their was no way the prop was faulty but that either my shaft was bent or the engine was out of line (they are MC dealers). However I stuggle to believe this as the old prop worked fine.

Their is no way the shaft could have been bent or the engine could have moved in the period between changing the props over.

This leads me to think that the prop I bought was unbalaced or their is some sercet to fitting them that I dont know.

I'm going to refit my original prop this weekend and try it. I suspect everthing will be ok. But does anyone have any other suggestions or tips on fitting props??????


07-11-2007, 03:20 PM
drug addiction is a terrible thing ... take the "reconditioned" prop back and get a brand new cnc'd prop from OJ or Acme ... what you likely experienced was a prop that had been reconditioned by hand and it was not in balance.

07-11-2007, 03:24 PM
no secret fittings, just the locking vinly nut, cotter key (stainless steel) and the prop with the correct shaft diameter ... is your shaft keyed or splined?

07-11-2007, 03:25 PM
Thats The Problem...."reconditioned"

Call Max At Skier To Skier


07-11-2007, 03:43 PM
no secret fittings, just the locking vinly nut, cotter key (stainless steel) and the prop with the correct shaft diameter ... is your shaft keyed or splined?

The shaft is keyed.

I guess I may have to look at getting a new prop then. You guys wont believe how much they cost in the UK Legend 3 blade $660!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!

The recon was $320!!!!!!!

07-11-2007, 03:48 PM
If it's your 88 ProStar then it's likely to be a tapered shaft with a keyway. I'm not up on prop installation on those, but IIRC it is possible to get it on cockeyed enough that you can get significant vibration. Search here for installation info if you don't already have that.

Sizzler bought a prop here in the US and had it shipped to England for a lot less money than you can buy them for over there.

07-11-2007, 03:51 PM
No its the 96 205 but it does have a keyed shaft.

07-11-2007, 03:54 PM
No its the 96 205 but it does have a keyed shaft.

Same concept then. Look at this post... (http://www.tmcowners.com/teamtalk/showpost.php?p=235376&postcount=6)

07-11-2007, 03:57 PM
dh- don't give up on the reconditioned prop yet. There most definitely is a trick to getting a keyed prop seated properly on a tapered shaft. First put the prop all the way on the shaft without the key. Use a marker or pencil to mark how far the front of the propeller goes onto the shaft. Remove the prop, and reinstall with the key in place. Make sure the prop goes all the way back to the mark you made. If you put the key in too far, the prop may hang up on it, before it seats fully on the tapered shaft, which may cause severe vibration.

07-11-2007, 04:00 PM
If you do end up getting a new prop, look at this thread (http://www.tmcowners.com/teamtalk/showthread.php?t=9515&page=2&highlight=acme).

Also, consider PM'ing Sizzler about the particulars of propellers and Englishmen. Seems to me he's sitting on a dinged prop as we speak.

07-11-2007, 04:09 PM
I would also recommend trying to refit the reconditioned prop before you take it back. It may be something as simple as a bit of fabric or dirt that misaligned it enough to cause the vibration.

Oh, and like Bigmac said, PM Sizzler...he's got a buddy bringing one back to the UK from Sanibel, FL very soon...

07-11-2007, 04:14 PM
What butter said applies. Makes sure that your key is not holding the prop out from being completely seated on the shaft. The other thing to do to remove minor vibrations (MINOR, not what you're experiencing) due to the prop bore being possibly slighlty out of round, or having a casting ridge, is to "lap" the prop onto the shaft.
Install the prop w/out the key and use valve grinding compound between the prop bore and the shaft. Spin the prop w/ the compound to grind or mate the 2 sufaces completely.
Again, doesn't sound like your problem. Either the key is holding the prop from fully seating on the tapered shaft (key may be slightly too big, can remedy by grinding down the key a bit), or the prop you bought is out of balance. Good luck.
FWIW, read up on some of the prop threads. I just replaced my original OJ 13x13 prop w/ an ACME 543 (13x11.5) CNC machined prop and it eliminated what little vibration I had previously.

07-11-2007, 04:35 PM
I was in the same condition as you except my prop decided to bounce off some rocks, which made me decide to buy a new prop and maintain the old fixed prop as a back up. I bought my new Acme from Wakeside.com:


I bought a little different pitch to get more torque. I have been very happy with the Acme prop. I think with the fancy storage bag I am into the prop for about $430.