Yanmar 3YM30 with KM2P-1 tranny vibration

[Ebenezer]

Vibration, enough to cause mechanical seal to leak (in forward not in reverse). I know the transmission was operated for a period of time (maybe 50 hours) with way too much oil which has been corrected.I have read that too much oil can cause excessive vibration but wonder if there is permanent damage from that. I have replaced the motor mounts and done a proper alignment. The engine runs very smooth when out of gear. The vibration is not enough to feel from the helm but not sure what is a normal amount of vibration. I had the boat out for bottom painting recently and the prop and cutlass look good. The engine has about 500 hours. If anyone has any ideas I would sure appreciate your comments.

 

[dasreboot]

what kind of engine and transmission? cone clutch transmissions can suffer from cone slip, which feels like a very bad vibration whemn it is slipping. It also usually only slips in forward or reverse. I have heard that too much oil allows the cone to slip more as it is bathed in oil instead of splash lubricated. i put too much in mine when i rebuilt it, I immediately got my oil change pump and pumped it out. then i refilled with the correct amount. so it is possible to damage it, although the fix might just be to disassemble and deglaze the cones.