Kanzaki KM3A transmission rebuild

[markwbird]

The drivetrain vibration Odessy continues. I have replaced the prop shaft, cutlass bearing, engine mounts, damper plate, balanced the prop and aligned everything to nth degree. I still get a heavy vibration that shakes the engine heavily. This only occurs in forward gear and only when the boat is moving through the water and not even all the time under these conditions. I’m thinking it must something in the transmission. Damaged gears? Anyone else experience this? Anyone have experience rebuilding this transmission? I am concerned about parts availability.
Any thoughts are appreciated.

 

[kloudie1]

Dunno, Mark.. could be that the forward clutch cones are slipping?
Any Yanmar parts supplier should be able to get the parts.. If it is a slipping cone clutch, sometimes they can be cleaned and the faces un-glazed.. sometimes they have to be replaced (about $500 for the part)

 

[markwbird]

Thanks for the input, Kloudie. What is the source of that drawing?

 

[kloudie1]

Yanmar service manual..
EDIT: Scroll down to chapter 10 and there is some good stuff .. From the "Boat Info" , "Owner Resources", and General Downloads" on this site:
https://sbo.sailboatowners.com/downloads/Hunter_gen_75448537.pdf

 

[JohnAC]

I was wondering what the outcome was. My new to me P42 will vibrate a lot when pushing hard, checked shaft,prop balance and alignment. The gear box also whines in fwd.

Thanks John

 

[Charles Erwin]

Kloudie is probably right. De- glaze the cones - matter of fine sandpaper p600 or finer. Very likely few parts required apart from gaskets. Needs to go back together surgically clean. Anyway - what have you got to loose? I would do it because the process is cheap and simple.

Are you doing the work or is someone else?

Either way - there are two things in addition. Rule out whether the strut is fractured and make sure shaft alignment is dead on. Also make certain the cable pulls the shifting arm full forward such that the cone is fully engaged.

Try the article below: Also I have a spread sheet that calculate the Harden offsets if you are interested.

Charles

 

[StargazerP303]

One of the first thing I would check for Proper Linkage forward-neutral-reverse to make sure it the right deg's. My unit was off and under load conditions would rumble my engine. hope this helps!

 

[NYSail]

I see your list however you don’t say if you had your shaft checked for trueness? They do slightly bend and can be straightened by a prop shop. My old boat I brought down my shaft and prop when I bought the boat and again 6 years later and sure enough both needed to be adjusted..... never hit anything.

Good luck
Greg

 

[Mike Oldak]

THANKS ALL!! After almost 40 years I think my shaking is a little of all of the above. I've replaced the engine mounts this year for the first time (based on prior postings), they aligned the shaft and engine, but may need a haul out to finalize everything. My diesel mechanic also suggested that the last 2 years in the Chesapeake Bay produced a lot of algae, so in the haul out we'll be sure to clean the prop. As for the cone, if we take the trans out I'll probably opt for a new cone clutch since the trans probably deserves it after almost 40 years and I only have to pay 25% of the bill (thank you partners).