Yanmar 3GMF engine transmission information wanted

M

Mike Oldak

.
Jan 22, 2008
309
Hunter 34 Herrington South, MD
I've read a number of posts talking about the 3GM engines on the H34s jumping all around. I just replaced the engine mounts on my 1984 Yanmar for the first time (who knew they wore out). But I still get a lot of chatter at lower speeds. I will haul the boat this year and make sure that the prop is clean from 2 years of bad algae growth (one suggested solution). I was also reading that there is a cone clutch in the transmission that if replaced could fix the problem. As a too avid DIY, I was wondering if anyone know the brand/model of our transmission so I could locate a service manual and perhaps rebuild it myself.

This is from a 1983? or 4 Hunter 34.

Thanks
 
Claude L.-Auger

Claude L.-Auger

.
Dec 14, 2003
1,401
Hunter 34 Lake of Two Mountains, QC, Can
My 84 Hunter 34 with the 3GM30F engine has the Kanzaki transmission as per attached pix. Most 3GM30 engine have either the KM3P or the KM3A transmission. Clatter at low speed (forward) is indeed an indication of a worn clutch. On mine it happened up to 1400 RPM and disappeared upwards of that. Repairing the tranny solved the issue in my case. Be aware that the clatter could also be caused by worn engine mounts (yours are new), worn cutlass bearing or misalignment. Attached is the engine parts catalog where you'll find some info on the tranny.
 

Attachments

Last edited:
  • Like
Likes: sail sfbay
SabreToothedEngineer

SabreToothedEngineer

.
Jan 13, 2015
95
Hunter 34 Deep Bay, BC
I have an '83 H34 with the 3GMF engine and the Kanzaki KBW10 transmission (just to give you the model that goes with the 3GMF). The reason for posting, though, is that we had a strong vibration at all but low speed that was getting worse as time passed. We suspected - and investigated - all sorts of things, from a bent shaft to the transmission and motor mounts. In the end, it turned out to be that where the FRP muffler passes through two ribs on its way aft, the vibration over time had worn through the muffler shell enough that it was actually leaking a bit of water. It was also transmitting sound really effectively into the hull. The more it wore, the thinner the wall and better the sound transmission, hence thin increase over time. I pulled the muffler, reglassed it, and reinstalled it with two pieces of split silicone hose to insulate it from the ribs. The difference in vibration was startling; we couldn't believe that so much vibration could be coming from such a simple thing.

I can easily see this being mistaken for a transmission problem. The only difference is that you're saying it's worse at low speed, and we noticed it far more at higher rpm. It would be an easy thing to check and rule out, though.
 
M

markwbird

.
Nov 26, 2012
1,653
Hunter 34 Berkeley
Had the same issue. Kanzaki KM3a. It can be rebuilt. Cost you about $800. Replace the cone clutch. Do not try to recondition the old one.
 
Whatfiero1

Whatfiero1

.
Mar 29, 2017
576
Hunter 30t 9805 littlecreek
Had that problem with a cone clutch in a volvo and just switched to 40 weight oil. Then to 50 when I sold it
 
kloudie1

kloudie1

.
Nov 6, 2006
9,893
Hunter 34 Mandeville Louisiana
My '85 model 3 GMF has a Kanzaki KM 3 A
If the cone is what ya need, the part # is 177070-03070.. cost is around $580 (American)
Be sure to verify that the shift mechanism on the transmission is going to fully forward when you shift it there from the pedestal.
 
Last edited:
R

Randy Church

.
Feb 28, 2006
79
Hunter 34 610 Narragansett Bay
Mike, when I purchased my 34 back in 2005 I experienced 'severe' vibration of the boat when in forward only and at a certain speed. After having the prop tuned, shaft replaced and other expensive options, because of diagnoses by boat yard and other experienced individuals, the vibration remained. Then I found on the Forum someone who told me to ensure the transmission was '100%' in forward....not '99.9%'. We examined the cable and found it wasn't fully engaging in forward, did an adjustment on the cable/linkage and sure enough the problem was solved. No problems since. Hope this helps.
 
  • Like
Likes: Mike Oldak and Whatfiero1
M

Mike Oldak

.
Jan 22, 2008
309
Hunter 34 Herrington South, MD
Randy Church said:
Mike, when I purchased my 34 back in 2005 I experienced 'severe' vibration of the boat when in forward only and at a certain speed. After having the prop tuned, shaft replaced and other expensive options, because of diagnoses by boat yard and other experienced individuals, the vibration remained. Then I found on the Forum someone who told me to ensure the transmission was '100%' in forward....not '99.9%'. We examined the cable and found it wasn't fully engaging in forward, did an adjustment on the cable/linkage and sure enough the problem was solved. No problems since. Hope this helps.
Click to expand
Thanks Randy, I'll check the transmission cable next time I'm on the boat.
 
M

markwbird

.
Nov 26, 2012
1,653
Hunter 34 Berkeley
Years ago I worked at a Quick Lube in Lubbock, TX. Guy comes in with car and a couple of bananas and asks if we could stuff the bananas into the rear differential box through the oil check hole. You might try that.
 
A

Artey1

.
Jul 18, 2019
165
Hunter 34 Oklahoma
markwbird said:
Years ago I worked at a Quick Lube in Lubbock, TX. Guy comes in with car and a couple of bananas and asks if we could stuff the bananas into the rear differential box through the oil check hole. You might try that.
Click to expand
I can't tell if you're serious here...
 
dmax

dmax

.
Jul 29, 2018
980
O'Day 35 Buzzards Bay
Bananna peels is an old trick used to quiet down a noisy differential just prior to selling it :)
 
You must log in or register to reply here.

Top Bottom