Yep, another query..on a Yanmar 2GMF..engine clatter

SeanP

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Jun 6, 2017
87
Hunter 31 Portland
Sean- I assume you have checked your shaft alignment- is the vibration at a certain rpm range ? I get a vibration between 24-2600 on my engine- not bad but noticeable from other rpm ranges. Do you have a folding or feathering prop that perhaps is not fully deploying. Or I guess a fixed prop could be unbalanced but I am only taking a SWAG here- I am not a very good diagnostician but those would be my thoughts-
The vibration begins at 1100 rpm and gets worse all the way up to 2600-2700 RPM. I have a fixed prop. The weird thing is that all is perfect on the way out for a sail and then coming back in once I fire her back up it's vibration city!
 
Feb 27, 2004
172
Hunter 335 North East, MD
I am thinking shaft alignment- I assume you don't get this vibration at the dock when powering up in neutral ?
 

SeanP

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Jun 6, 2017
87
Hunter 31 Portland
I am thinking shaft alignment- I assume you don't get this vibration at the dock when powering up in neutral ?
In neutral at all RPMs there is zero vibration. If it is shaft alignment why do you think that when I fire her up and motor out of the bay to raise the sails...She runs smooth (in gear). After a day of sailing, she vibrates like crazy when I start her back up. In summary there is an intermittent vibration that is baffling! Cheers. Sean
 
Nov 26, 2014
51
HUNTER h31 Northport L.I.
Could it be clutch or transmission not engaged completely, My boat did something similar when the cable was not adjusted correctly , and it did not go completely in to forward gear. After cable adjusted properly all went away.
 
Jan 30, 2012
1,123
Nor'Sea 27 "Kiwanda" Portland/ Anacortes
The symptoms vanish motoring out and return after sailing? So something about sailing effects your propulsion.

When you put up the sails for the day what position (forward, neutral, reverse) do you place your gear lever? You have a fixed pitch prop so your prop rotates when sailing - albeit the in the reverse rotation of the gear lever position.

This problem is significant enough that Yanmar for example says keep the transmission in neutral (actually they say damage will occur if you don't go with neutral when sailing/engine off. ) Other transmissions can show similar symptoms. In any case - consider neutral when sailing thus to eliminate jamming the internal components of the transmission together due to sailing induced reverse prop shaft rotation that really cannot be avoided with a fixed pitch propeller.

I could be wrong here but maybe try neutral and see what happens?

Charles
 
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SeanP

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Jun 6, 2017
87
Hunter 31 Portland
Good morning,

Thanks for the comments Charles and Sailermaned. It appears that the starboard rear engine mount is shot. When I sail the motor shifts on the three remaining mounts and causes the racket when I start her back up.

Btw, I do sail with the transmission in neutral. Trying to track down an engine mount replacement. More on this story as I progress.

Cheers,

Sean
 
Jul 11, 2016
18
Hunter 326 Oriental, NC
I've been working quite a bit. It sounds like you have it worked out now though. Congratulations and hope the mount fixes the issue.
 

MitchM

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Jan 20, 2005
1,021
Nauticat 321 pilothouse 32 Erie PA
re: The vibration issue: have you checked your engine mounts and the amount of face out at 12 - 3 6 and 9 o'clock on the the p - shaft coupler ?
 

SeanP

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Jun 6, 2017
87
Hunter 31 Portland
re: The vibration issue: have you checked your engine mounts and the amount of face out at 12 - 3 6 and 9 o'clock on the the p - shaft coupler ?
Hi, the rear starboard engine mount is shot, and so I have ordered replacements for both rear units. Not sure what 'amount of face out.." refers to nor the p-shaft you reference? Thanks! Sean