grinding noise when i shift into gear on my Yanmar3gm30F

[Ian.marshack]

I have a Yanmar 3GM30F engine with a Kanzaki clutch plate KM2P with a gear ratio 2.62 I am having a issue of a new grinding noise when i shift into gear after the engine has warmed up and every this is running normal. the engine noise sounds like its coming from the transmission area and the engine jumps around on the mounts like its struggling to move the propeller shaft. the noise happens in forward and reverse, but if i keep the engine in gear and rev it the noise stops in a few seconds. But the noise is slowly getting worse and lasting longer and the engine is jumping around more and more. When the engine is not on I can easily spin the shaft and there isn't a build up on my prop or anything around it. My cutlets bearing isn't too tight and I believe my engine mounts and shaft angle are in alignment. I replaced the transmission oil and didn't see and wear or metal in the old transmission fluid. Why does my engine make this grinding noise then when I shift into forward or reverse? My engine is in a Westsail28 located in Honolulu HI

[skipperpete]

Welcome to cruisers forum ian.marshack. I suggest taking a look through the little window on the gearbox bell housing with a strong flashlight, often the drive/damper plate fail in a way that allows broken damper springs to get loose and rattle.... loudly. Or you might simply have a bad gearbox bearing. Believing that the alignment is good is not enough , it needs to be verified.
There also exists the possibility that the propeller is fouled or the shaft has a hard calcium buildup inside the stern bearing.

[Ian.marshack]

I will check that out next and let you know how it goes. Mahalo