Yanmar 2GM20F, exhaust elbow temperature sensor (cheap version of the nasa)

[frlrubett]

First year with a 2GM and on first trip had overheating due to seaweed in the inlet but we noticed smoke out the exhaust and stopped quickly and solved problem.

As a precaution purchased one of these..

https://www.amazon.co.uk/Thermomete...rds=temperature+sensor&qid=1685896244&sr=8-41

And attached it to the outside of exhaust elbow with a jubilee clip.

When under no load with a 14c degree sea temperature, the idle temperature read 26c degrees. When under heavy load, pushing into 1.5kt of tide saw temperatures around 39c degrees. When cruising in no tide temperature was about 35c degrees. Everytime the engine was unloaded the temperature dropped back to around 30c.

Does this seem normal?

 

[38mess]

I don't know if it's normal, but on my Perkins M30 the exhaust elbow is cold to the touch after a few hours motoring

 

[Tranona]

The 2GM I assume is the seawater cooled version and the elbow will be hot and changeable depending on load. The M30 is heat exchanger cooled

 

[Aquanaught]

I have a temperature guage/alarm (Silicon Marine) with the probe in the exhaust about 150mm down from the elbow. The readings I get from a Beta 30 are broadly similar to yours (taken last summer).
Beta 30 h.p. slack water, boat hull clean and new antifoul
Ambient sea water temp 16 deg.C

Engine Revs	Speed OG kts	Exhaust temp. C
2000	4.2	33
2200	4.5	33
2500	5.0	34
2800	6.0	36
3000	6.3	38
3300	7.0	42
3500 (max)	7.2	43

Obvioiusly differing boats/engines will have differing readings but hope this helps. Cruising at 2400/2500 (5 kts) exhaust tempr 34c is norm. for me in summer and appears to be similar to your readings.

 

[frlrubett]

I have a temperature guage/alarm (Silicon Marine) with the probe in the exhaust about 150mm down from the elbow. The readings I get from a Beta 30 are broadly similar to yours (taken last summer).
Beta 30 h.p. slack water, boat hull clean and new antifoul
Ambient sea water temp 16 deg.C

​

Engine Revs	Speed OG kts	Exhaust temp. C
2000	4.2	33
2200	4.5	33
2500	5.0	34
2800	6.0	36
3000	6.3	38
3300	7.0	42
3500 (max)	7.2	43

Obvioiusly differing boats/engines will have differing readings but hope this helps. Cruising at 2400/2500 (5 kts) exhaust tempr 34c is norm. for me in summer and appears to be similar to your readings.

Yeah, much more exact than my method - but yes it feels the same. Might try and go max revs for a few minutes and check the hottest it can be under "normal" conditions then I have a bench mark to get worried at in the future!

 

[jamie N]

I've similar on my 10hp motor, which rarely gets above 30C and is fitted in the same way.

 

[Dellquay13]

Has anyone done a simple buzzer and red light for an overheating exhaust? It would probably make an earlier warning of a problem than the engine overheating sensor and the warning light in the engine switch panel, especially for the exhaust hose itself. The digital display is nice but I’d like a buzzer too

 

[jamie N]

Yup, I connected one of these to one of these, and all is well.

 

[frlrubett]

Have looked into making one with a buzzer using a BBC Microbit, that Nasa one is nice to have but a lot of £££!