I have an 81' H30 with a Yanmar 2QM15. I had a temp guage installed and it basically stays on the bottom unless you shut the engine off after fast cruising. Is this engine supposed to have thermostat? If so, where should I install/check for one?
- Status
- Not open for further replies.
T
THOMAS WIENER
THERMOSTAT
All diesel engines must have a thermostat,otherwise your engine works underkooled,the results will be bad combustion leading to fill with carbon your combustion chamber,valves,etc. Consult your user manual,its very easy to install. Tom
All diesel engines must have a thermostat,otherwise your engine works underkooled,the results will be bad combustion leading to fill with carbon your combustion chamber,valves,etc. Consult your user manual,its very easy to install. Tom
S
Sam Lust
Nothing is wrong
Your raw water cooled Yanmar does in fact have a thermostat and is probably functioning OK. To prove it, remove it from the housing, which is located somewhere at the top front of the engine. Suspend it in a pan of water with a thermometer and heat it up, You should see it open at the temperature stamped somewhere on the thermostat. I have had one that was stuck open, which is far preferable to stuck closed. As to the low reading on your new guage; It is probably reading correct. The raw water cooled enging runs very cool, around 130 to 140 if I recall, which is just below the running range of the majority of available guages. Everything I founfd in the West Marine and Defender catalogs start at 120. I believe you can get the proper guage and sender set from Mack Boring, if you can talk to the right guy there.
Your raw water cooled Yanmar does in fact have a thermostat and is probably functioning OK. To prove it, remove it from the housing, which is located somewhere at the top front of the engine. Suspend it in a pan of water with a thermometer and heat it up, You should see it open at the temperature stamped somewhere on the thermostat. I have had one that was stuck open, which is far preferable to stuck closed. As to the low reading on your new guage; It is probably reading correct. The raw water cooled enging runs very cool, around 130 to 140 if I recall, which is just below the running range of the majority of available guages. Everything I founfd in the West Marine and Defender catalogs start at 120. I believe you can get the proper guage and sender set from Mack Boring, if you can talk to the right guy there.
O
OBX Sailor
Mine is the same way
I have a Yanmar 3QM30 which I added a temp guage last year. I went through the same delemia with my guage. It only reads about 125-130 degrees. Checked with the local Yanmar mechanic and he said that is normal. After a year all is well!
I have a Yanmar 3QM30 which I added a temp guage last year. I went through the same delemia with my guage. It only reads about 125-130 degrees. Checked with the local Yanmar mechanic and he said that is normal. After a year all is well!
G
Gene Gruender
Gene Gruender
Your thermostats (there are two of them) are in the small housing located on top of the exhaust manifold toward the front. I seem to recall that there are 4 - 10 mm head bolts holding it on.
Your thermostats (there are two of them) are in the small housing located on top of the exhaust manifold toward the front. I seem to recall that there are 4 - 10 mm head bolts holding it on.
G
Gene Gruender
Well, the 3qm30 does
I just started reading the whole post again and realized the original question was about a 3qm15 (I've seen 3qm20's, but not a 15, and not a 3qm30, but my guess is that it's still on top of the exhausst manifold.
I just started reading the whole post again and realized the original question was about a 3qm15 (I've seen 3qm20's, but not a 15, and not a 3qm30, but my guess is that it's still on top of the exhausst manifold.
F
Fred G
J
Jim Logan
2QM15 thermostat opens @110f, full open @130f
According to the 2qm15 manual, the raw water cooled 2qm15 thermostat opens at around 110 degrees farenheit, and is fully open @ 130 f. So if your 2qm15 is operating correctly, it should never get any hotter than around 130f. Sam is correct about the cooler temperature holding down scale formation in the cooling passages - you need to get a manual for the 2qm15, as it is a different animal than the GM series, for example the max rpm is 3000, NOT 3600 as the GM series. You could make expensive noises running it at too high an rpm.
According to the 2qm15 manual, the raw water cooled 2qm15 thermostat opens at around 110 degrees farenheit, and is fully open @ 130 f. So if your 2qm15 is operating correctly, it should never get any hotter than around 130f. Sam is correct about the cooler temperature holding down scale formation in the cooling passages - you need to get a manual for the 2qm15, as it is a different animal than the GM series, for example the max rpm is 3000, NOT 3600 as the GM series. You could make expensive noises running it at too high an rpm.
- Status
- Not open for further replies.