Yanmar 3QM30

[Walt G]

My 37c is powered by a Yanmar 3QM30, converted from salt water to fresh water cooling with a SenDure heat exchanger. Anyone out there know if hotter thermostats are available for this? Would like to get into the 180 degree range vs the approx 140 range in the original engine. Right now I'm using a gate valve on the antifreeze side to get the temp up, but would rather have thermostats do this if possible. Second, engine specs call for about 8 quarts of oil, but with the angle it sits, about 4 quarts brings the dipstick up to full. Anyone know for sure whether to use 4 or 8 quarts.Thanks, Capt Walt, s/v Moonshine.

 

[Ed Schenck]

Eight is too much...

Hi Walt,My Yanmar book is on the the H37C and I have a 2QM20, but I am positive that 8 quarts is way too much. Give Torresen or Mack Boring a jingle. Here's Torresen's site:http://bsd.torresen.com/yanmar/I just got a new thermostat from them.

 

[Ed Schenck]

Sorry, eight IS correct...

according to my 2QM20/3QM30 manual. My 2QM20 is only 5 liters, but yours is 7 liters(/.91=7.7 quarts). And I have also wondered about the engine mounting angle but my dipstick is at the rear of the engine and I assumed the "Full" mark must compensate for that.But I have also noticed that there is very little distance between the marks. And I never get anything like 5 liters when I pump it out. It's enough of a concern that I just bought a better pump a couple of weeks ago but have not changed my oil yet.When you drain yours do you check the stick and do you think it is really empty? Hopefully Torresen was able to clear this up.

 

[Ed Schenck]

Me again.

Last night I changed the oil after a good warmup. I have this new hand pump from West Marine that is excellent. It has a wire inside the tube so it won't curl up in the crankcase. It was coming out slowly and there was only about a quart in the container. After moving the tube around and making sure air could get in there was gurgling and suddenly it was filling the tank. I must have pulled 8 to 10 quarts out of there! It was obviously never emptied properly. I only had three quarts with me and I did not turn the engine over to fill the new filter. It measured about 1/8" from the full mark which I think is close for my 2QM20 rated at 5 liters. With the filter filled it should take another 1.5 quarts. But I was surprised, the engine angle is quite pronounced.Also wanted to install a thermostat. Luckily I checked the new gasket first, it was a square four-holer. My 2QM is diamond-shaped with two holes!

 

[Ernie Rodriguez]

Thermostats

I don't have a 3QM yanmar, but I do have a Sendure- Heat Exchanger used to convert the salt water cooled 3GM Yanmar engine and found out that the normal thermostat for the salt water cooled engine is radically different in design than the thermostat for the Yanmar installed fresh water cooled system. The thermostat for the salt water cooled engines is set for 110 Deg F, but the Sendure Heat exchanger apparantly cannot keep up with the exchange required, so the engine runs hotter than the 110 deg setting as the thermostat must go wide open. Putting a higher temperature thermostat in place of the 110 deg thermostat resulted in much higher temperatures, almost to the point of sounding the buzzer. Looking carefully at the two thermostats, the difference becomes quite apparant as the 110 deg (salt water) has a bigger opening than the higher temperature one for fresh water. Check it out carefully if you decide to go to a higher temperature thermostat.