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Yanmar 2gmf stuck in reverse gear

10K views 14 replies 7 participants last post by  casey1999 
#1 · (Edited)
Hi all -- I recently acquired a 1983 Pearson 303, which I'm liking very much. It has a Yanmar 2GMF 13 hp 2-cylinder diesel, which runs like a champ. This evening, however, I discovered, to my distress, that the transmission appears to be stuck in reverse, which created some difficulty in getting back onto my mooring in a 3-knot current in the Hudson River.

Some weeks ago I experienced some difficulty getting it to go *into* reverse, but that seemed to fix itself.

I have a bad feeling that the problem is in the transmission, not in the shifter cable, which seems to move freely.

Anybody ever have a problem like this? Any suggestions for things I should try, or check out?

Many thanks!
 
#8 ·
If you have a Kanzaki-Hurth transmission you should use ATF.



Many folks put motor oil in these, and if you have oil in there I'd flush it (run, drain, fill, repeat 3 times)

that said, I cant imagine that the wrong oil would cause it to lock up in reverse. If you are lucky the shift lever is loose and rotating freely on the actuator shaft.
 
#10 ·
Okay, so I wriggled my way down to the gearbox -- it's not very accessible,
to say the least. The nameplate is on the starboard side, which is
*completely* inaccessible without a power saw, but I was able to snake
my cellphone around and take some pictures.

Near as I can make out, the nameplate reads:

MARINE GEAR - MODEL KM2-A
GEAR RATIO [Illegible -- 2.6? 2.5?]
OIL SAE 30/30 [Indistinct -- 20/30?] HD
OIL QTY 0.25 LI
NO [Illegible]
KANZAKI KOKYUKOKI MFG CO LTD

There is a bolt head labelled OIL on top, to starboard. There's another bolt
head on the port side, right at the aft lower edge of the side of the housing,
which I conjecture may be the oil drain. There's also an adjusting screw
on top, on the port side, which appears to affect the stiffness of the shift
detent.

I was able to muscle the gearbox out of reverse and into the various gears
a few times, so the immediate problem is solved for the moment. I didn't
have time to detach the shift cable, but I kinda think there may be some
stiffness both in the cable and in the box itself.

I'll try an oil change and top-up. Can anybody resolve the question
of oil type? My photos of the name plate are pretty fuzzy.

Many thanks!

By the way, I found it even harder to get back *out* of the gearbox
area than it was to get in. The boat's out on its mooring in the Hudson
River; I was by myself; it was getting dark; and I had a rather anxious
moment after one of my 65-year-old vertebrae gave me a nasty
reminder of its presence and discontent. The joys of sailing!
 
#11 ·
I feel your pain!

It is starting to sound like your shift cable is hanging up (which is good news for your wallet, not so great for your back). The next step is to disconnect the shifter cable from the transmission and see if you can select forward and reverse manually directly on the transmission. that will tell you where to turn next.

the KM2-A is a traditional cone-clutch transmission, so you would be using 30 weight motor oil, not ATF.

these manuals have a chapter devoted to your transmission:

The yanmar service manual:
Boatinfo - Yanmar Service Manual for 1GM, 2GM, 3GM, 3HM

The shop manual (see chapter 10, p199):
http://j30.us/files/YanmarGM&HMWorkshopManual.pdf
 
#13 ·
Don't try to shift it without the engine running and don't put it in gear with the prop spinning while sailing, as it can jam and do other nasty things to the gearbox innards.
Read the manual to see whether it should remain in neutral when sailing. My 2GM 20 owner's manual explicitly says leave it in neutral but I won't speculate on other models about which I know nothing......
 
#14 ·
On the subject of oil: The gearbox nameplate appears to specify (if I'm reading it right) SAE 20/30 HD.

Two questions:

1) Does this make sense, or am I reading it wrong?

2) How important is the HD part? Automotive suppliers I've called have single-weight SAE 30, but not HD, and when they hear the word 'diesel' they tell me I probably want the HD.

Okay, three questions:

3) Where is the HD version to be had? Is this stuff un-shippable, can't be ordered online, etc. ?

Thanks in advance from the poor ignorant n00b.
 
#15 · (Edited)
On the subject of oil: The gearbox nameplate appears to specify (if I'm reading it right) SAE 20/30 HD.

Two questions:

1) Does this make sense, or am I reading it wrong?

2) How important is the HD part? Automotive suppliers I've called have single-weight SAE 30, but not HD, and when they hear the word 'diesel' they tell me I probably want the HD.

Okay, three questions:

3) Where is the HD version to be had? Is this stuff un-shippable, can't be ordered online, etc. ?

Thanks in advance from the poor ignorant n00b.
My gear box says the 30/40 HD. So I can use either 30 weight or 40 weight oil. I use the 30 weight and you can too. My engine calls for 30 weight for the temp range I operate in. So I can use the same oil in my engine- makes life easier as need to have on hand only one type of oil. Check your manual if you can do the same. You must use Diesel rated oil in the engine- It should be also rated Heavy Duty. DO NOT USE GASOLINE ENGINE OIL in the engine.

I get my gear and engine oil (for a yanmar 3gmd) at Walmart. I get the Rotella (Shell Oil I think) Straight 30 weight oil that is rated for Diesels- Note jug says HD of front- Heavy Duty. It comes in a 4 quart plastic jug and sells for about $17. West Marine sells the same oil but at about $5 more. I use the same oil in my engine- but my manual says straigh 30 weight (diesel rated) is ok. The 30 wt should be good for your transmission. Check your engine manual if it is ok for the engine. Make sure you use oil rated for Diesel engines, like the Rotella T1.

Here is a source:
Shell Rotella 550019857-3PK T1 30 Motor Oil - 1 Gallon (Pack of 3) : Amazon.com : Automotive@@AMEPARAM@@http://ecx.images-amazon.com/images/I/41yUiqtSkLL.@@AMEPARAM@@41yUiqtSkLL

Rotella® T1 is an easy-flow single grade oil provides quality lubrication consistent performance and excellent wear protection in diesel engines. Low ash content to minimize formation of deposits and to help keep intake ports clean. Outstanding oxidation resistance to help maximize service life. Excellent rust and corrosion protection. Optimized dispersants to help prevent engine sludge and varnish deposits.

What others have said is correct. My engine will not come out of gear if it is left in gear while sailing. The force on the prop and prop shaft jam the gears. Keep her in neutral while sailing- and let prop free spin. You can install shaft brake if you do not like the spinning, but unless you are going to cross an ocean, not really needed.

As others have said, do not over fill the gear box or the engine with oil. Looks like the gear box only takes 0.25 Li about 1/4 of a quart of oil- not much!.

Be carefull what bolts you loosen on the engine or the transmission, you could accidently change and adjustment you cannot get back.

The best way to get the oil out is by sucking in out through the dip stick hole. Many marine engines do not have a drain plug. By draining the oil you could easily flood your bilge with oil and have a big coast guard fine if any gets pumped over board.

I know this is expensive, but it has worked well for me and saves much time (I have tried the hand pumps and found they do not work well):

http://www.westmarine.com/webapp/wcs/stores/servlet/Product_11151_10001_347537_-1?ci_src
 
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