Chatter underway with engine

Apr 2, 2018
10
Catalina 310 175 Lake Hartwell, Georgia
Ray,
Thanks. I'm almost sure it is one of these 4 items. I am betting on a improperly installed cutlass, since it didn't make this sound on sea trials before purchase and the cutlass replacement.
 
Apr 2, 2018
10
Catalina 310 175 Lake Hartwell, Georgia
Don't think it's the zinc ball on the shaft- I dove and checked that, the prop (which is a fixed,3-blade) to be sure it wasn't loose and the shaft itself- it did not appear to have any play at the strut. Probably just going to have to pull the boat to eliminate some causes.
Thanks to all for the ideas! It has been very helpful. I hope some day I can return the favor.
-B
 
Aug 13, 2012
533
Catalina 270 Ottawa
I would bet the clattering is a result of a miss aligned shaft.
Is it possible that this sound is coming from shaft (misaligned or out of balance) hitting the shaft log. I think it would be more noticeable outside (in the cockpit) than in the noisy engine room.
 
Apr 2, 2018
10
Catalina 310 175 Lake Hartwell, Georgia
Thanks. Any suggestions on how to determine if the shaft is misaligned while she's still in the water?
 
Mar 6, 2008
331
Catalina 310 Scott Creek, VA
You can loosen the coupling bolts and check with a feeler gauge at each of the four quadrants to see how close the alignment is. Last year I pulled my engine to replace the damper plate and found the aft two engine mounts were shot. Mine is 2003 #218 with less than 1000 hours. Lots of other good ideas here, but the damper plate is a known issue with the C310 engine installation, and the OEM mounts are at/beyond their service life. How long have you been experiencing the chatter? Mine had been getting progressively worse and the spline was practically worn through.
 

Attachments

DaveJ

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Apr 2, 2013
449
Catalina 310 Niagara-on-the-Lake
Anytime work is done on the hard that may affect alignment, the alignment should be checked a couple of days after the boat goes back into the water. The hull will settle to a different shape than it had on the stands.
Cheers