I’ve had to separate the shaft from my coupling several times.  It has always 
been an long, arduous process.  I can’t imagine how it would ever work its way 
loose.  The first time I had it apart, I even sanded the inside of the coupling 
to allow the shaft to slide back in place without too much effort.


With you engine in forward gear, the prop should be trying to push the shaft 
into the coupler.  Do you spend a lot of time in reverse?  ;-) 


A deeper dimple might capture the set screws better.  They should never come 
loose.  I recommend Loctite blue.  In this application, you could probably use 
the red variety.  Applying some heat to the screws makes removal fairly easy, 
if it ever needs to be done.


I agree with others that the root cause may be vibration.  Pulling the shaft to 
check it would be prudent, if you’re into the project this far.  Also, examine 
the prop for any abnormalities.  Finally, how are the engine mounts, especially 
when the engine is under load?  Excessive movement may exacerbate your coupling 


My $.02 worth.





Jake Brodersen

C&C 35 Mk-III “Midnight Mistress”

Hampton VA




From: CnC-List [] On Behalf Of William 
Walker via CnC-List
Sent: Tuesday, September 20, 2016 16:17
Subject: Stus-List Prop Shaft coupling


Some may remember that around mid summer I posted that my prop shaft had pulled 
out of coupling.  Mine has two bolts which go through coupling and into small 
dimples drilled into shaft.  They were wired in and over time the ends had worn 
off and allowed shaft to pull out when reversed was applied to prop.  Some on 
list checked and had similar problems.  I was surprised so many
Well, on haul out I discover it has happened again, with the new bolts.  
Haven't pulled them yet to see, but shaft pulled enough to show key and the 
dimples, still in place.  
No excessive vibration or anything.  
Bolts still appear tight.
Thinking maybe of going with two set screws in each hole, one snugged, another 
on top. 
Love to hear thoughts from listers with some experience. 
Bill Walker
Evening Star
CNC 36
Pentwater, Michigan


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