Yanmar 2GM HELP

[loup30s]

I'm looking to convert to inboard cooling with after market heat exchanger.
Any help or ideas would be great as I do not know where to hook up and close off the raw water colling.

THANKS for any help
Lou

[overbored]

why? it will be expensive and requires a lot of parts for no real gain. you will need a heat exchanger, new exhaust, different thermosat, raw water pump and a lot more hoses. you will still need the raw water inlet and outlet which will connect to the new rawwater pump and heat exchanger . the old pump will serv as the fresh water pump. there are companys that make conversion kits.

[loup30s]

I'm taking the boat out to the salt water and want to keep salt out it.
I have an after market heat ex changer and pump but like to know how to plumb from original manifold as I'm not too sure.

[overbored]

the engine is made to be used in salt water. most of them installed in the 70's are still in salt and no problems. if you still want to you have to circulate the salt water thur one side of the heat exchanger and back out at the exhaust. then the fresh water is circulated thur the engine and the other side of the heat exchanger as a closed loop. the trick is at the exhaust, you need a fresh water exhaust manifold so the fresh water cools the first section of the exhaust and then there is a connection for the salt water in the second section of the exhaust manifold. so now you will have two pumps to service instead of one and a exhaust manifold heat exchanger to clean every year. again the salt water will not hurt the engine there are hundreds of thousands of these engines running in salt water, all you will do is have an experimental boat engine that may or may not cool properly when all you need to do is splash it and motor off.

[Rockter]

...and if you ever move your boat to fresh water, don't let the motor freeze.
I did.

I would leave the motor as-is if it is working.

Don't mess with it unless it is giving tropuble.

[HUGOSALT]

I wanted to convert my raw watercooled 3GM when it was new
26 years ago, Mack Boring (Yanmar distributor)convinced me not to convert...they said not to worry...they were right. Still going strong.
The raw water cooled units run at lower temp, (approx 140*) as
not to separate the salt, then the fresh water cooled units.
If concerned one can flush motor every year with rydlyme and/or
fit valve near water intake where you can flush motor with fresh
water easily and often. (never with a hose under pressure)

[Hudsonian]

I have a Sendure heat exchanger conversion on my 2GM. It came that way from Tillotson-Pearson. Sendure still makes the kit.

Additionally, you will need an expansion tank, hose and clamps, a raw water pump, pulleys, and a belt. The raw water pump supplied with my system is a Jabsco 2760-0001. Mounted to it is a Die-cast v-belt pulley 3-1/2" OD, 3/8"bore. Both are still readily available. You'll need to fabricate mounting brackets for the raw water pump and the heat exchanger. I'd guess that the entire installation would take a shade tree mechanic about three hours.

if you want to maintain the ability to crank the engine by hand you'll need to lengthen the shaft of the hand crank.

[JimsCAL]

This may help.

Atomic 4 Fresh Water Cooling System - Electric Antifreeze Pump

[Hudsonian]

The electric antifreeze pump looks pretty neat. It certainly would be cheaper than the Jabsco pump, fabricated mount, barbs, pulley, pulley on the engine shaft, and belt. It would eliminate the need to lengthen the shaft on the hand crank and eliminate the pinching hazard from an unprotected belt.

[SlowButSteady]

I considered converting my 2gm20 to FW cooling. But, the guys at a diesel shop/parts-retailer (S&W Diesel, in Wilmington, CA) basically talked me out of it. They said that as long as the zincs are changed on a regular basis, corrosion isn't really a problem in these little Yanmars (with the exception of the mixing elbow). They pointed out that the part I brought in (the plate that holds the cylinder head zinc) essentially looked brand new once the salt was blasted off. Also, my guess is that it would cost you $1000 to $1500 to do the conversion. You might get a bit less carbon build up, and the emissions might go down a but at the higher operating temps. But, since the horsepower ratings are identical for the raw water and freshwater versions of these engines, I doubt there would be any significant increase in power. All together, it probably isn't worth the time or expense.