yanmar 2gm km2a tran

[billangiep]

North you don't have to remove the cover plate. Loosen the one bolt on the shift arm and you can rotate as needed. I believe the lower plug on the case holds a spring and ball (detent) for F N R. Once you have the shift arm correctly orientated (90 degrees from the cable to the shift arm while in neutral) the adjustments are made with the shift cable and spring joint.
Bill,

[Northeaster]

Billang - Thanks again for all of the help.
So, just so I am clear. I know that my throttle cable needs to have a tension clamp on it (did this last year), as the rpms would reduce otherwise. But, are you sure that the shift cable needs this type of clamp as well, in addition to the spring joint cable connector? Last year, I didn't have either a tension clamp, or a spring joint, on the shift cable - and obviously, it didn't work well!!

[Northeaster]

Billang - Finally found that old thread on Yanmarhelp.com, where it was recommended to lap the mating surface of the drive gear - which the cone slipps against - I referred to it as lapping the cone itself.

Just thought I would provide the source of the info!

Quote!!!
Had similar problem with 2GM 15 several times.
The inner face of the gear that the bronze clutch cone spins into has become glazed, resulting in slippage when put into gear. Cone will heat up because of slippage give a few clunks the engage. Solution is to dissamble gear box, apply a bit of valve lapping compound to inner face of the gear, lap the cone into the face for about a minute, clean everything carefully and reassemble.
There is an adjustment on the shift lever houseing that must be made to ensure equal travel in foreward and reverse, this is critical to avoid reaccurance of problem.


and ..

The cone does not wear, the race that it spins into gets glazed from slippage and prevents proper mating of the two faces. while this slipping is occuring the cone heats up and expands, you get the clunking sounds then away you go.
The spring joint insures that a positive pressure is always on the shift lever, if there isn't, slippage can occur from cable creep.

End quote!

Full thread available at link:
Yanmarhelp.com Message Forum - Yanmar marine diesel engine help & advice -> 2GM20 Forward Gear Problem

[bernard50]

Hey Guys,
Can anyone help me,....I had my cone drive in my KM2A lapped and have used it for 30 hours. It now again is causing the entire engine to shudder ONLY in forward gear,...only at operating temp,...and only between around 900rpm to 1800 rpm. The engine oil may well be something to consider...but why does it not happen in reverse??
Any help would be much appreciated.
Bernard

[r.furborough]

bernard50 et. al.

You are suffering from a maladjusted shift mechanism/cable. The KM2/KM3 and the down angle 'a' variants are very sensitive to this and possibly a weak detent spring on the shift mechanism itself. I do not discount a worn cone clutch, but the shudder/banging of the transmission is a classic sign of this.

[Northeaster]

Does it do it when you manually shift the lever on the transmission? (instead of shifting the lever in the cockpit).

For those who have read all of this thread. I (and my auto mechanic brother) took my 25 year old K2Mp transmission off of my Yanmar 2GM last winter. Took it apart, lapped the cones, and replaced reconfigured the shifting lever wit hthe proper Yanmar parts, and Morse cable.

I have had zero problems last season or this season and am extremely happy with the results.
Thanks to all those who gave advice!!

[jeffls]

I have a spare kanzkai km2a transimission. I am posting it on ebay but if I don't get any interest I'll be putting it back in storage. If you still need one send me a pm.