Need Help: Prop Shaft Jam Nut Won’t Budge

Jun 14, 2025
158
Hunter 1981 30 Chesapeake
The saying "the enemy of good enough is better" comes to mind...

dj
AS far as I know the propeller and shaft are functional and seem in decent condition. Is there any reason to do further work while the nuts are off and it's out of the water? Looking for ideas.
 
Jan 7, 2011
5,659
Oday 322 East Chicago, IN
AS far as I know the propeller and shaft are functional and seem in decent condition. Is there any reason to do further work while the nuts are off and it's out of the water? Looking for ideas.
You may want to check the cutlass bearing, and the shaft and coupling, and the stuffing box.

Greg
 
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Likes: JoeWhite
Jan 7, 2011
5,659
Oday 322 East Chicago, IN
That's a good idea, although this boat is equipped with a PSS dripless shaft seal. I could inspect it, or even replace the rubber if necessary.
Yep. The bellows need to be replaced periodically. Based on some of your other findings, I would bet the PO didn’t follow this maintenance recommendation either.

In order to replace the bellows, you need to separate the shaft and coupling…hence my suggestion to check that also.

You are making some good progress!


Greg
 
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Likes: Timm R Oday25
Jun 14, 2025
158
Hunter 1981 30 Chesapeake
Yep. The bellows need to be replaced periodically. Based on some of your other findings, I would bet the PO didn’t follow this maintenance recommendation either.

In order to replace the bellows, you need to separate the shaft and coupling…hence my suggestion to check that also.

You are making some good progress!


Greg
Thank you. I do believe this PSS seal was installed 3 years ago when a new engine was put in the boat. It may have some life left or it may not. It's hard for me to say. I'll have to do a little search on what the other parts are that you speak of.
 
Jan 7, 2011
5,659
Oday 322 East Chicago, IN
The shaft coupling connects the shaft to the transmission. If it was replaced 3 years ago, it should be good.
 

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
23,252
CAL 35 Cruiser #21 moored EVERETT WA
This link may help.
If your data is accurate you have at least 3 more years before recommended replacement.
PSS FAQ - PSS Seal recommends that the bellows be replaced once every 6 years.
The set screws are a one and done item.
 

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
23,252
CAL 35 Cruiser #21 moored EVERETT WA
When the time comes to do the replacement, inspect your shaft for wear or pitting. Have the shaft inspected for any warp or untrue condition.
When you remove the coupler from the shaft, you should have the shaft fitted and faced with the new coupler. This will give you known true 90º face at the coupler. You can then connect to the transmission and finish the alignment by adjusting the fitting at the coupler. This provides a “near perfect” connection from transmission to Propeller and minimizes vibration of the prop shaft assembly.
 

dLj

.
Mar 23, 2017
4,421
Belliure 41 Back in the Chesapeake
AS far as I know the propeller and shaft are functional and seem in decent condition. Is there any reason to do further work while the nuts are off and it's out of the water? Looking for ideas.
Well, I see i came into the conversation late. I hadn't seen the subsequent posts that you had removed the nuts when I posted my first comment...

So given where you are at, definitely get new nuts.

I'd inspect the whole system.

Look for wear in the cutlass bearing. Pull the flange off the engine and pull the shaft out far enough to inspect in all locations that you can't see when it's installed. Look for any scoring of the shaft where it goes through the hull and Cutlass bearing. Inspect the PSS bellows and the sealing surface. Get your prop inspected.

If everything looks good - reassemble. If any component looks questionable, replace.

If you have shaft scoring, you should just replace all the above (possibly not the prop)..

dj