Yanmar Transmission Problem

[nv5l]

I was motoring last winter at about 3,000 rpms for a few hours and all the sudden it started making all sorts of noise and I lost all propulsion. I backed off the throttle and took her out of gear and the noise stopped. After checking various combinations, I found that the only time I got the noise was in gear, forward or reverse, with power, not at idle. However, at idle, the shaft would turn normally.

A friend suggested it was probably the dampening disk, but after pulling the transmission and the disk, I can't find any problem. I've got the transmission sitting in from of me taken almost completely apart and can't see anything wrong with it. Nothing's broken or worn.

I did find lots of red stuff on the output spline and retaining nut, but figured that might have been locktight. I also found red covering the disk, but since everything was rusty, I didn't find that surprising either.

Any suggestions of what to else to check? Could the disk be bad even if it doesn't look broken?


btw, it's a Yanmar 3HMF w/ KBW10E.

thanks...
don

[boden36]

How is your prop shaft bearing? Also, is your prop on tight?
Regards,
Richard.

[Laidback]

Originally Posted by nv5l

I was motoring last winter at about 3,000 rpms for a few hours and all the sudden it started making all sorts of noise and I lost all propulsion. after pulling the transmission and the disk, I also found red covering the disk, but since everything was rusty, I didn't find that surprising either.


btw, it's a Yanmar 3HMF w/ KBW10E.

thanks...
don

Why was the Disc rusty ? What made it Rust ?

[nv5l]

Sorry for the late reply, had some connectivity issues.

I've got it out, and everything looks good, except the disk drive springs are a bit loose and there's a groove worn in the thrust washers. Looks like it wore down enough to make the clutch slip under load, and the loose disk drive accounted for the noise -- it was slipping and grabbing several times a second and the disk drive would bank each time. Before this happened, I'd hear a clunk each time I put her into gear.

Parts should be hear by the end of the week, so I hope to finish her up and get back in the water by the end of the month. Thanks for all the replies.

[delmarrey]

Had a friend who had to replace his thrust washers a couple times. He ended up going to a full service transmission vs his pleasure trans.