Yanmar 2gmf 13hp cooling system

[Mattcia123]

hey all,

Got my first Diesel engine recently, yanmar 2gmf 13 hp, question about the cooling system. The boat clearly pumps seawater, but it looks like it also has the parts of the engine for fresh water. Engine is running fine and I see water coming out of the back. Is it supposed to be both? I thought the letter "f" in the model means fresh water cooled. Can anyone clear this up for me?

 

[Davidasailor26]

You are correct that the F means it's a fresh water cooled model. There are two separate cooling circuits there. The fresh water circuit goes from a water pump, around the block, possibly to a hot water heater, through a heat exchanger, and back to the water pump (maybe not in that order). The sea water gets pulled from under the boat through a separate pump, through the heat exchanger, taking heat out of the fresh water, then into the exhaust.

 

[Mattcia123]

Thank you that helps. Also I found a few of these copper colored tubes coming out of the radiator that don't look they are attached to anything, looks like they just drain. 2 of them are at the bottom and 1 at th top. is that normal? Here are some pictures:

 

[kloudie1]

Welcome to the forums !
Poke around on the site and you can find lots of great info on the engine and boat itself..
Here is a diagram from the Yanmar shop manual that shows the water systems .. The sea water only flows through the tubes of the heat exchanger.. The engine coolant (antifreeze) is in the block and the outside of the tubes in the heat exchanger..
Again, Welcome Aboard..

 

[kloudie1]

Yup, those are drain tubes.. they are labeled in the picture..

 

[Mattcia123]

Thanks for the welcome. And appreciate the diagram. Do you all th drain tubes drain the coolant? Or air?

 

[kloudie1]

Pretty sure the rearmost one drains seawater from the heat exchanger tubes and the others drain coolant from the heatex housing and block.. The seawater (raw water) one would have to have the front water supply hose removed to let air in to let it drain ..

 

[NYSail]

They drain the coolant. Use a container and open each up. Makes flushing system easy.....

Good luck

Greg

 

[StargazerP303]

hey all,

Got my first Diesel engine recently, yanmar 2gmf 13 hp, question about the cooling system. The boat clearly pumps seawater, but it looks like it also has the parts of the engine for fresh water. Engine is running fine and I see water coming out of the back. Is it supposed to be both? I thought the letter "f" in the model means fresh water cooled. Can anyone clear this up for me?

I too have a 2GMF in my Pearson 303. here's a helpful link to some idea's..
https://forums.sailboatowners.com/i...-yanmar-2gm-f-core-cleaning-made-easy.169371/
I also have all the manuals if you need something just give me a jingle..
welcome and good luck.. Capt. Rob StarGazer II

 

[dennismenace111]

Those hoses are the drain petcocks used when you want to drain the coolant from the engine block. Put the end in a bucket or empty gallon milk jug, open the petcock and the antifreeze and water mixture will drain. Be sure to replace the coolant will the same type that came out.

 

[Mattcia123]

Thank you everyone for the helpful resources and tips, this forum is amazing.

Fair winds everyone

SV Second Wind

 

[RoyS]

You may find that the drain valves are frozen. In that case just remove them for possible repair or just replace. Also, if you open the drain valve and nothing comes out poke a wire up into the drain to clear any sediment. You must also open something upstream to admit air for draining. Pull out your thermostat for inspection as well. Then clean and bandage your knuckles.

 

[StargazerP303]

After doing some long 2GMF13 research, I found out that there is no Zink to install in this motor. However, what's interesting is the thermostat gasket is a special one. It was manufactured with Zink, where the others are a very Black like paper material gasket. The right one is - Gray and Glossy. So watch out for the one you install.
Best Regards, Capt. Rob

 

[Davidasailor26]

A gasket manufactured with zinc? I wouldn't have guessed that. I would have thought that would lead to a bad seal as the zinc corrodes.

 

[StargazerP303]

A gasket manufactured with zinc? I wouldn't have guessed that. I would have thought that would lead to a bad seal as the zinc corrodes.

I thought that too... but that's what a guy from Yanmar told me when I replaced mine. It did look like the edges of the seal installed and where turning to powder or corroding slightly on edges. Maybe some other people will weigh in here!
regards.