2gm cooling system

[Mark Smith]

I own a 2gmf Yanmar, and I also own a 1-2-3-gm yanmar service manual. My problem is that the 2gm cooling system in the manual is not the same as the motor I own. They clearly show the cooling system with the raw water pump (running off a belt) but what they dont show is what I have a (leaking) behind a second and unshown (pump) running off the belt on the top front of the motor. The motor is freshwater cooled, is this the problem? I need to know how to get gaskets for the top pump (that does not exist) as any Yanmar owner should know I need at the very least a explanation of what I need. I am assuming that it would have to be a fresh water pump, but I need part #s, or an explanation. Thanks,Mark M Smith

 

[Craig Pringle]

2GMF pump leak

Sounds like an add on fw cooling system, in which case the lower belt driven pump becomes the coolnnt circ pump. The pump mounted on top of the engine, probobly a jabsco, serves as the raw water pump. I assume you have verified that the leak isn't coming from the cover plate. After discounting that and the hose connections the only other source is the pump seal, indicated by dripping at a small weep hole in the pump body. Normally this seal can be replaced, but if the shaft is heavily scored at the seal mot shops opt to replace the entire pump.

 

[Richard]

pumps

usualy a small "v" belt driven water pump is for raw sea water and is mounted next to the crank pully. The bolt to the block pump( also belt driven) will be for the engine fresh water or antifreeze, check the color of the leaking water. You can perssure test the cooling system of the engine at the raditor cap..... Raw water pumps can leak with out loss of coolent

 

[Ernie Rodriguez]

A similar cooling system

I have a similar cooling system on my 3GMD Yanmar. It is a sea water cooled engine as per the Yanmar Service manual, but modified by Hunter as a freshwater cooled engine with addition of a SENDURE kit. The kit consists of a heat exchanger (mounted on the back of the engine, just above the transmission), a second water pump, ITT Jabsco model 2760 mounted on a bracket just above the injector pump, and a drive pulley mounter on the engine. The Jabsco pump is used for pumping the sea water and the Yanmar pump is used for pumping the coolant. The impeller for the Jabsco pump looks identical to the Yanmar pump. A complete set of replacement parts is available from ITT Jabsco. The pump costs about $170 new.hope this helps.Ernie