Yanmar 3GM(D) Shakes and Loud - Transmission?

[Badsanta]

I would check the prop before anything else.

[geoffr]

Looking at the manual it askes for the springs to be coated in The manual states the springs on the shifter be coated in non drying liquid packing - being new to this I don't know what this is .. can someone educate me ?

With respect to the KM2A and KM3A - the manual says they are the same:

Note: Models KM2A and KM3A reduction and reverse gear boxes, shafts and gears are the same except for the following items:

• No. of gear teeth (derives different gear ratios.)
• Distance between bearings for input and output shafts.
• Clutch case, mounting flange.

Originally Posted by never monday

Mark the side shifter plate so you can put it back exactly. It's designed to float around and be adjustable. Pull it off and look at the shift spur. See if there is excessive wear in the forward side. It can be flipped and reinstalled. I know it can on the KM2A. I think it can on the 3. If it's in good shape then it's probably a tear down to replace the drive cone.

[nonam]

Its not just the rubber on the engine mounts.The stud can shear under the lower adjuster nut.But you have probably pushed and pulled on the engine enough now to reveal if this was a problem.

[captfolly]

hey Geoff....we will (hopefully) be hauling our snowgoose next week and if there is anything we can look at, check, order, compare, take pics of, or whatever, just contact us....we have a yanmar 3gm30f with the sillette drive...

fair winds,

George & Doris

[felixsail]

We are having same problem, Geoff.... What was your resolution? Thanks! Felix

[TaoJones]

Originally Posted by felixsail

We are having same problem, Geoff.... What was your resolution? Thanks! Felix

All of the activity, above, surrounding Geoff's shaking issue occurred last November, felixsail. Geoff hasn't been active at CF since April, so it may indeed be a long shot. Good luck.

TaoJones

[Chief Engineer]

I would suspect motor mounts first.

Especially the one under the secondary fuel filter.

They are susceptible to deterioration from diesel fuel spills.

[geoffr]

Felixsail,
We haven't fully figured out the problem, however I believe it is an alignment issue related to the motor mounts. One of the mounts is not secured down properly and does shift - sometimes the shake is worse than other days..

G.

[felixsail]

Thanks for replies. Geoff, wondering if you ever removed and checked out the transmission to eliminate it as a possible cause? Felix

[Badsanta]

Fix the motor mount and check your idle speed. the cable may have slipped or stretched causing the motor to run much to slowly causing more vibration.

[geoffr]

Felix,
No we haven't removed the transmission, however from the tests we did we determined that it most likely isn't the problem. We found if I stood on the transmission before it started shaking we didn't see the problem, so assuming it is a misalignment due to the engine mount(s).

G.

[r.furborough]

I think you have an adjustment problem, either with the selector mechanism on the side of the transmission or of the shift cable. Last year I had a similar problem, the transmission would be ok initially, then under load it would 'bounce' until the boat stopped accelerating. I determined the problem to be a weak or misadjusted detent on the forward gear or a bad adjustment of the cable. Made the necessary adjustments and all is OK now. The Kanzaki transmissions, when they slip tend to slip and then bite when slightly out of adjustment, this manifests itself as a very heavy vibration.......

[Chief Engineer]

Do you have the Yanmar motor mounts?


or the mount that has a single rubber bushing?


Pushing and pulling on the engine will not tell you if a mount is bad

You need to put a prybar under the leg of the engine that the mount goes thru and pry up.

Mounts with the single bushing (if the vulcanization is shot) will pound as the engine torque will lift that side of the engine