SailNet Community - View Single Post - Transmission output flange fell off Yanmar 2QM15 - Theories re: why?
View Single Post
post #24 of Old 01-30-2013
eherlihy
Learning the HARD way...
 
eherlihy's Avatar
 
Join Date: Jan 2007
Location: Boston / Ft Myers Area
Posts: 4,088
Thanks: 159
Thanked 110 Times in 107 Posts
Rep Power: 9
 
Re: Transmission output flange fell off Yanmar 2QM15 - Theories re: why?

DISCLAIMER: I do not own a Yanmar, not have I ever done anything other than bleed one.

Looking at your photos, and description, I suspect that the "machining" of the inside of the coupling was done on the boat. All it would take is very little play, and the shifting in and out of gear would start to hammer the inner spilnes of that coupling. Eventually, the hammering would shear off the splines, and with a little torque in the right direction, the nut would be spun off too.

I suggest that there may be little pieces of splines somewhere in your bilge.

To repair: get a new coupling - yours is clearly toast -, a new lock nut, AND a new washer (part #2 in the above illustration). I would go so far as to use lapping compound and Prussian Blue to mate the coupling and the output shaft. To get an idea of what I am talking about, look at this article by Maine Sail pertaining to lap fitting a prop. Once the coupling and the output shaft have been prepared, use a torque wrench to apply the right amount of torque to the lock nut. Once torqued to spec, stake the nut.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

USCG Licensed OUPV Captain, ASA 101/103/104/105/106/118 Instructor - Also certified in Marine Electrical Systems


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Last edited by eherlihy; 02-13-2013 at 08:52 AM.
eherlihy is offline  
Quote Share with Facebook
 
 
For the best viewing experience please update your browser to Google Chrome