Yanmar engine identification

[sailscallny]

Hi guys
I have an 1981 hunter 36'

The yanmar engine plate identifies engine as "2Qm-20H"

Is the Q really a F.Up. "G" ?

I can find - 2GM-20F

So no 2"Q"M

No 20"H". Only "F"

What's up with that

Trying to find cam chain all rusted and stiff

Larry
Sails Call
NY

 

[kloudie1]

Most likely correct: 2QM 20H.. the model that preceded the GM series of Yanmars.. to my knowledge, no interchangeable parts.. If the chain that is all rusted is that external one at the front of the engine, that is only for the hand crank.. Your Yanmar guys (maybe Toad Marine? http://shop.toadmarinesupply.com/marine_diesel_direct/Yanmar/) can help with parts etc..
The shop manual and parts manuals are available on line.. and here on the site.

 

[sailscallny]

Thanks

 

[kloudie1]

The "H" means it has a multi-plate transmission clutch and so uses auto trans fluid instead of motor oil as some do to lube the transmission.. The lack of an "F" means that it is sea water cooled and does not have a heat exchanger unless someone along the way modified it ..

 

[rardiH36]

Dear Sailscallny:

I note you joined SBO just yesterday. New Owner?

I have a 1980 Hunter 36. If you haven't discovered it yet, SBO has a subform called Cherubini Hunters. That is what we have. You will find lots of information about our models.

Regarding the engine.

The 2QM20 in our boats is in fact Yanmar designed to be sea water cooled. But Hunter modified the cooling circuit so that instead anti-freeze does circulate through the engine and an externally mounted heat exchanger. My heat exchanger is mounted in the starboard lazarrete. Hunter installed a pump on the alternator belt to circulate seawater through the heat exchanger and then back out through the exhaust elbow. I guess it's possible you have a boat that wasn't modified in this manner. But all other 1980-82 owners I have seen on the Cherubini forum also report this setup. I believe many of the Cherubini 37's were also delivered this way.

Please see this thread from a several years ago. Particularly Post #7 which describes the cooling system -- along with diagrams: https://forums.sailboatowners.com/i...from-h36-80-82-new-owner.167367/#post-1164114.

 

[rardiH36]

Hi guys
Trying to find cam chain all rusted and stiff
Sails Call
NY

As Kloudie1 already advised, the chain only serves for hand-cranking the engine. It doesn't rotate at all when the engine is running. In theory, one can hand crank to start the engine. In practice notoriously difficult to do. And if your engine is mounted like mine, the hand crank impacts on the wood engine compartment frame. So can't even get a full revolution on the thing. The hand crank's best use is to rotate the crankshaft to put the cylinders in the proper position for adjusting the valve clearance.

Since the chain is only needed for the above reasons, it need not be perfect. So instead of finding new, perhaps soaking it for a while in an oil bath and/or PB Blaster, will get it pliable again. And serviceable for its purpose? Others might know of better methods to restore (or at least make somewhat serviceable) a rusty chain.

 

[MarcMag]

Hello all. I bought at 1981 Hunter 36 a couple days ago... I'd like to connect with you guys if possible as you both know a lot more about this boat than I do.... I know nothing.... just getting started.