C34 2002 transmission failure…what do I do?

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Thanks Ron.  I think you are right.  It just looks like a flat plate.  So I am convinced the transmission is the problem.


I put a twin disk in and am very happy with the way it works. Did a write up of what it entails.
1987 mk1 a work in progress #618

Ron Hill

3412 : That might work on your M25XP with a Hurth 50, but Les has a M35BC engine with a Hurth 100 transmission

A thought
Ron, Apache #788


I am back in port now after a few days on the lake with our annual guy cruise (on a Catalina 355).

Looking at the damper plate it looks like the grooves are pretty worn down and stripped.  There are a lot of metal shavings in the bottom of the bell housing.

I am going to order a new damper plate. It is the elastomer one that is part Z417.  Any one know the best p;ace to get one quickly?

Our mechanic at the club thinks the tranny is OK.  No end play in bearings and it seem to be working when tested by hand.

Any tips on removing the damper plate?  I am hoping I ca do this without removing the bell housing.  Is that possible?



Colonel Butler

Les: I changed out the damper plate on my 2006 MKII M35B a year ago. The original was too stiff and caused a rattle sound at low RPM. I ordered a new one from https://www.pyiinc.com/damper-plates.html. Miles at PYI recommended the R&D model 22AM4 which has more deflection and absorbed the irregular rotation speed of the engine at low RPM. (The flywheel on this engine is a bit too light). Cost was $239.00 US.

If you want the original stiffer one I removed, it's yours for the cost of shipping. It is in perfect shape it is a R&D model 22B4. I'm in Niagara-on-the-Lake Ontario.

I removed the bell housing to get at the damper plate.

2006 Catalina 34MkII "Calypso"
Hull #1746
Niagara-on-the-Lake Sailing Club
Niagara-on-the-Lake ON Canada

Ron Hill

Les : Like I said I believe that the "Damper Plate" is a misnomer and the elastomeric type bearing. It should be a simple align the splines to fit on the engine and transmission so it just slides ON /OFF.

If you have metal filings you need to CAREFULLY inspect the splines on both the engine drive and the transmission.

In one of your posts you mention:
"Thanks Ron.  I think you are right.  It just looks like a flat plate.  So I am convinced the transmission is the problem".  You are either looking at the flywheel or you have a M25XP type damper plate!!!!!! 

Look at the center and the M35BC engine(inside the bell housing) has a small elastomeric "damper" in the center.  Maybe 3"? in diameter.

A few thoughts

A few thoughts

Ron, Apache #788


Here is the shot of my damper plate.  Not much left of the teeth.  I am now thinking the transmission is OK.   I  hope to change out the damper plate without removing the bell housing.  I have the aftermarket replacement on order from Catalina Direct.


Dave DeAre

Les, I replaced the damper plate on my 2002 without removing the bell housing.
Good Luck!
2002 34, roller main, tall rig
Burnham Harbor, Chicago


Same for me Just turn the pulley in the front of your motor and you will have access to the bolt
L'Apache hull#1377  1997 Quebec Canada universal 35bc