Temp guage 2qm20 yanmar

[sailinbob1]

I've read the posts saying that a temp guage isn't necessary because, normally, there's an alarm, and warning light. I've got a 1972 Allied Chance 30/30 that someone stuffed the engine into. There's no light,or alarm. Engine, though it looks a bit crusty,runs well,and my new volt,amp,and oil pressure guages all are working fine. My question is this,where would I put the water temp sensor, since I have nothing else? Granted,I generally only use the engine leaving,returning ,or if I'm trying to avoid unexpected trouble, but I've got the gauge,so may as well use it. The Pdf I have is crap,and since there was a warning light,I should be able to add the sensor there,where ever there is. Thank you. Any suggestions would be greatly appreciated. Bob.

[Cheechako]

Maybe someone will answer on location if you have neither, I cant remember where mine was.
Try Google Images: "temperature sender location" Is that 2 QM or GM?

[sailinbob1]

Talked to Chad, at Mastery Engine Center ,our local yanmar dealer, here in St Petersburg, and he says it's next to the back zinc plate on top of the engine. Since I need to replace the zinc anyway, seems like an opportune time for both. Thanks,I'll keep you posted.

[delmarrey]

The owners manual should show where a guage should go. And I would recommend having, at least, an alarm THAT WORKS.

[sailinbob1]

I pulled up a pdf,but,though it shows a schematic of the sensor, it doesn't show the location on the engine. I'm replacing an instrument cluster, that included a mechanical temp guage. The guage I bought is electrical. Chad,at Mastery Engine Center in St Petersburg, sent me an exploded view drawing of the sensor located at the top of the engine, next tone the aft zinc plate. I figure, if it had a warning light,and ,later,a mechanical guage,perhaps I can get a sensor to work in that position. If I have to, I'll buy a mechanical guage. Plan on checking it out tomorrow. I definitely agree,I need something. Thanks.

[wayne.b]

Originally Posted by sailinbob1

I've read the posts saying that a temp guage isn't necessary because, normally, there's an alarm, and warning light. I've got a 1972 Allied Chance 30/30 that someone stuffed the engine into. There's no light,or alarm. Engine, though it looks a bit crusty,runs well,and my new volt,amp,and oil pressure guages all are working fine. My question is this,where would I put the water temp sensor, since I have nothing else? Granted,I generally only use the engine leaving,returning ,or if I'm trying to avoid unexpected trouble, but I've got the gauge,so may as well use it. The Pdf I have is crap,and since there was a warning light,I should be able to add the sensor there,where ever there is. Thank you. Any suggestions would be greatly appreciated. Bob.

===

If the engine is fresh water cooled (with a heat exchanger), I'd want the sensor located to read the coolant temperature, normally about 180 degrees F. If the engine is raw water cooled, the sensor should be on or near the cylinder head where the coolant exits.

[sailinbob1]

Strangely enough I believe it's both. I found a fresh water drain coch,and water exits the exhaust when the engine is running. I have yet to see a coolant/fresh water fill cap, but from what I've read,so far,this is a possible set up for this engine. I'm not a mechanic. I was a tooler/carpenter at Trident Shipworks for 10 years. Kinda figuring it out, as I go along.the engine is in quite a small space. Thanks for your input. Any suggestions would be greatly appreciated.

[wayne.b]

Originally Posted by sailinbob1

Strangely enough I believe it's both. I found a fresh water drain coch,and water exits the exhaust when the engine is running. I have yet to see a coolant/fresh water fill cap, but from what I've read,so far,this is a possible set up for this engine. I'm not a mechanic. I was a tooler/carpenter at Trident Shipworks for 10 years. Kinda figuring it out, as I go along.the engine is in quite a small space. Thanks for your input. Any suggestions would be greatly appreciated.

===

Follow the flow of water from your intake seacock to the raw water impeller pump. If the output of the pump goes to a heat exchanger then you have a fresh water (closed coolant) engine. After the heat exchanger it would be normal for the raw water to exit via the exhaust elbow.

If instead the output of your impeller pump goes to a thermostat housing and/or engine block/cylinder head, then you've got a raw water cooled engine.

In any case the critical temperature to measure is the cylinder head.

[sailinbob1]

Thanks a bunch. That's very helpful. I'll check it out tomorrow. I planned on spending the day jammed in the compartment anyway. I haven't noticed a thermostat housing, but then I haven't, exactly, looked for one either. Would placing the sensor where the warning light sensor,which was located next to the aft zinc at the top of the engine, be the logical place to add the guage sensor?

[Wotname]

Originally Posted by sailinbob1

Strangely enough I believe it's both. I found a fresh water drain coch,and water exits the exhaust when the engine is running. I have yet to see a coolant/fresh water fill cap, but from what I've read,so far,this is a possible set up for this engine. I'm not a mechanic. I was a tooler/carpenter at Trident Shipworks for 10 years. Kinda figuring it out, as I go along.the engine is in quite a small space. Thanks for your input. Any suggestions would be greatly appreciated.

That is a raw water cooled engine and be aware that the running temperature of the head will be between 100F and 125F (or maybe slightly higher). Check that your gauge is meaningful in this temperature range as most gauges are designed for freshwater cooled engines that operate at much higher temperatures.

The reason the raw water operates at low temps is that at any higher temps, the salt precipitates out of the seawater and clogs up the internal cooling galleries.

[sailinbob1]

Thanks for the info. I'll keep it in mind once I actually get the guage in. Which would you recommend? I've got an electrical guage,but I can get a mechanical, if it would be more accurate.

[Jura]

Because I have 2QM20 on my boat, after some screening of the net I have found 2QM20 service manual in pdf format-about 20MB of dates. If will be somebody interested...

[sailinbob1]

Originally Posted by Jura

Because I have 2QM20 on my boat, after some screening of the net I have found 2QM20 service manual in pdf format-about 20MB of dates. If will be somebody interested...

I found the owners manual pdf. It's not helpful, for this application. I did,however, find the sensor, so I'll have a good at it tomorrow. Thank you though.

[mjcook]

I have a 2GM20 and mounted my 'Engine Guard' alarm reading from the thermostat this seems to work well.

[sailinbob1]

Think I found my sensor next to the forward engine zink. Gonna check it out tomorrow. I believe a previous owner ,probably whoever installed the engine (The Allied Chance 30/30 came with a gas engine),replaced the light/alarm sensor, with a mechanical water temperature gauge.