2QM20 Yanmar

[pelicanj45]

Can anyone tell me the difference between a 2QM20F and a 2QM20H.
I need to replace my 2QM20F and I've found a 2QM20H. Wondering if it's a direct replacement.
Any in-put would be greatly appricated.

JC

 

[pfaffk]

If you link to you can get an explanation of the engine codes. http://shop.torresen.com/marine_die...getitle=Yanmar+Marine+Engine+Identification++

 

[zeehag]

my 2qm20h is raw water cooled. i believe the f is fresh water cooled--with radiator and antifreeze etc.....

 

[pelicanj45]

Thanks for the in-put.
Sounds like it's fresh water / raw water.
I'm sure I can re-pipe it for fresh water. I did the opposite when my fresh water pump sprung a leak and I had to order a new pump.

Tx's

JC

 

[Steve Dion]

JC: Where are you getting your motor from? I think I know of one that is out of the boat, but not sure if it is fresh water or raw water cooled.

My source is in California.

 

[Dan Hill]

I believe the "H" is for a land based piece of equipment but I may be wrong. Even so, I think the long block "block, crank, rods, pistons, head, valve train, fuel injection" are the same. Just need to dress it up with your marine components.

 

[pelicanj45]

JC: Where are you getting your motor from? I think I know of one that is out of the boat, but not sure if it is fresh water or raw water cooled.

My source is in California.

Steve Dion,
I found a 2QM20 on line at Diesel Engine Trader. I'm open to getting one almost any where in the U.S.
I have a crack on the out side of a water jacket. Been fighting it for two years. I've pulled the motor out twice using an auto-wrecker to hoist it out. (gonna put a string on it and call it a Yo Yo) Had it welded both times. They did a good job, just didn't lay enough weld bead. I've sealed it with JB Weld and that worked to the point where I now have a pin hole that I can't seal. So, I've used Bar's Leak, and that works but it's just a band-aid. I'm open to suggestions.

JC

 

[Steve Dion]

http://www.youtube.com/watch?v=zSOB08eHfh8

Youtube video of engine running before being removed from H30.

 

[rardiH36]

The H is definitely the raw water cooled variety. It's my model. But on my boat, Hunter modified it for close circuit cooling by adding an external heat exchanger on a bulkhead and a raw water pump was added to the alternator belt loop. The pump that is integral to the engine was converted from raw to anti-freeze circuit duty.

The "F" model has the heat exchanger and antifreeze tank/cap mounted directly to the engine.

From what I can gather from my 2QM series manual, other than the coolant circuits, the engines are the same. However because the H has raw water coursing through its insides, the thermostat is a 140F type to prevent salt water minerals from depositing irrevocably in the channels which happens at the higher ~170F temp for anti-freeze engines. The thermostat housing on the H will not accept the F thermostat. My engine, although now enjoying anti-freeze, is a 140F engine.

 

[pelicanj45]

Rardi,
the set-up you discribe is the same as mine. Hunter added it as an after market.
Thanks for the info.

JC

 

[rardiH36]

JC:

Sorry -- when I wrote my response, I didn't first look to see your boat model. Nice looking thing. (But you can appreciate I am partial to the Cherubini Hunter 36.) Also nice way you have enclosed the cockpit with canvas and flexible windows. Really adds to the living space. And you don't have to worry as much about the engine access hatch on the cockpit sole leaking!

Was your external heat exchanger placed in the port lazarette? Here is a picture of mine as it looks now. The red 1/2/Off switch shunts to my emergency start battery. For ever day power on/off I use the 1/2/Off switch at the nav station.

 

[pelicanj45]

Rardi,
I'm new and still wandering around on this site. If you posted a pic, I guess I don't know where to find it.
The cockpit enclosure is great for michigan. Early spring sailing and late fall sailing. Also it's nice when the weathers bad and I'm traveling. I also have zip in screens for hot bug infested summer nights.

 

[rardiH36]

Rardi,
I'm new and still wandering around on this site. If you posted a pic, I guess I don't know where to find it.
The cockpit enclosure is great for michigan. Early spring sailing and late fall sailing. Also it's nice when the weathers bad and I'm traveling. I also have zip in screens for hot bug infested summer nights.

jc:

My mind was on finishing the 40 year old swimming pool re-do project so I went back to it without thinking to add the picture.

Maintaining my sailboat is much more enjoyable.

Here is the photo. The heat exchanger is a Send-dure 2550. When I bought the boat, the baffle plates on each side of pipe had some holes, letting anti-freeze and raw water to interact. The tubes themselves however were in very good shape. A local radiator man that also does heat exchangers packed the holes with a thick layer of solder. All been working fine now for 5 years.



rardi

 

[rardiH36]

Rardi,
I'm new and still wandering around on this site. If you posted a pic, I guess I don't know where to find it.

In the off chance that you haven't discovered it, this site has a sub-forum dedicated to the Cherubini Hunters. It is fairly active with a good group of Hunter Cherubini enthusiasts.

http://forums.hunter.sailboatowners.com/forumdisplay.php?f=44

 

[kloudie1]

Rardi.. I like your idea of the luminescent tape or paint on the battery switch.. Makes that much easier to see and deal with at night, I'll bet.