Thermostat

Status
Not open for further replies.
T

Ted

I installed a temperature guage rather than rely upon the light. To my dismay, the indicator never even made it to 100 degrees. I am thinking that there must be a thermostat somewhere. Any ideas why this 2Gm in my 1979, 33 foot Hunter is running so cold?
 
Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
GM or QM?

Ted: Do you have a GM or QM. The QM is raw water cooled and they do not get very warm. I would suggest that you still have a buzzer in addition to your gauge. Unlike an automobile where you are sitting in from of an instrument panel, this NOT the case with a boat. If you are busy motoring in traffic or have someone else at the wheel the buzzer will alter you when you do not have time to look at a gauge.
 
E

Ed Schenck

Water temp.

Had the same concern with my 2QM20F. The 'F' is for fresh-water cooled, mine is not raw water cooled. I installed a new thermostat and it had no affect. Unless I motor for a considerable distance the gauge barely moves. But on the rare occasions when I motored for thirty or more minutes at over 2500 RPM it did register around 110 - 120 I guess. I agree with Steve, a buzzer would be nice. But my gauges do happen to be in my line of sight.
 
P

Pete

gauge/sending unit

Ted,you said you installed a gauge. Did you also install the CORRECT sending unit? there are different sending unit and must be matched to gauge.You can also check the actual water temp using a temperature gun instrument to see what the temp is at the block, thermostat housing, heat exhanger etc, etc.There is alot of info on adding gauges in the archive here on HOW and also a method of how to install a gauge and keep your warning light and buzzer in the Yanmar panel. Good Luck !
 
T

Ted

Thanks for the good info guys; but, do these engines (GM) have thermostats in them or does the water just flow right through?
 
E

Ed Schenck

Reread my post.

As I wrote there, I have changed my thermostat. If an old 2QM20 has a thermostat and you really have a 2GM(much newer)then you would think there is one. But then I found this on the Yanmar site: "Part Number: Yanmar 105582-49200 Description: THERMOSTAT FOR MOST GM (NOT F SERIES)" So maybe if yours is an 'F' series motor, meaning you have a heat exchanger and two water pumps, you do not. Or maybe it is a different part number but I could not find one. You could call Ike Torresen.
 
E

Ed Allen

yes

there normally is a thermostat in a 2 gm.but im inclined to agree with the previous guys. make sure your instrument and your sender are a pair. if one is sending apples and the other is looking for bannans your going to get fruit salad not the right temp reading.
 
S

Sam Lust

CCCCold

Raw water cooled Yanmars run cold. Plain and simple. The thermostat, with age, corrosion and marine growth tends to stick in the open position, causing the engine to never really come up to it's (very low) running temperature. Pull the thermostat, replace it, make sure your sender and gauge are compatable and are installed and wired properly. Rely on the original equipment warning screecher system. I don't know about you but while I do like to be aware of any temperature change trends, it is better to know that if something happens while I'm at the bow I'll be told about it audibly.
 
K

Ken Palmer

Back to the 2GM*box

My 1981 H33 also has a Yanmar 2GM. That is all the plate has, no "Q" or "F". To the best of my knowledge, the engine is cooled by raw water, pumped in from the lake, and there is no thermostat that I have ever found. I do not own the repair manual for the 2GM, but I bet the answer is there.*! Ken Palmer, S/V Liberty
 
O

OBX Sailor

My H-37 C Water temp

Last year I added a temp indicator to my waring system. My 3GM30 only gets to about 125 degrees. The local Yanmar mech says that this is correct and so does my manual. My gauge does read it but it is not in the center of the guage like most car indicators read.
 
Status
Not open for further replies.