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Discussion Starter #1
Hi Folks
Hi Folks

Have Beneteau 40 with yanmar 4JH4AE engine, KM35P cone clutch transmission.

Had transmission problem. The cone clutch was lapped and trans put back in. But I now get a vibration set in at 1200 rpm which goes away at 1600 rpm.

Would love to have some ideas before mechanic comes to look at things in two days time.

Could alignment problem come and go over this sort of range or could there be other causes.

thanks, JohnB40
 

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sounds like an out of balance shaft or prop, alignment - if done correctly, should be good across the operating range.

You can turn the shaft coupling 90 or 180 degrees, after marking it, to see if the problem changes or have a reputable shop check the prop and shaft.

Assuming it did NOT happen prior to the repair? Loose mount?
 

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Discussion Starter #3
Hi folks

Getting good comment ... thanks.

The vibration started after tranny repair 6 weeks ago. Problem is I left day after for a 6 week sail. My recollection is it was there from the start and we tried to avoid that 1200 to 1600 rpm range where it occurred. Could have become worse over the 6 weeks away but not sure.


Should have also said the vibration does not occur with engine in neutral.

I've no idea if the couplings on transmission and prop shaft were reconnected with the same holes matched up .... sounds like that might be a possible thing worth trying? That is, rotate shaft 90 degrees and rebolt. Do again etc to see if one position is good .... as you see I'm no expert!

thanks, JohnB40
 

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I've no idea if the couplings on transmission and prop shaft were reconnected with the same holes matched up .... sounds like that might be a possible thing worth trying? That is, rotate shaft 90 degrees and rebolt. Do again etc to see if one position is good .... as you see I'm no expert!

thanks, JohnB40
Yes, mark the "current" position, and then rotate the shaft 90 degrees at a time.
 

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Discussion Starter #6
Thanks folks. I feel much better informed ... never a bad thing. It does seem to have been just the alignment issue. Vibration seems to have been fixed.

Still concerned why Yanmar cone clutch would crap out after such a short period of use ... the KM35P trans seems to have a load of problems from searching the web. It was run as per Yanmar instuctions ... allow to spin while sailing. Ensure clutch cable adjusted. Change oil etc

JohnB40
 
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