[Amel Yacht Owners] Exhaust water temperature sensor 7MDKAL

Bill & Judy Rouse <yahoogroups@...>


I don't understand, or maybe I am confused or wrong...or, all of the above.

I believe that the exhaust elbow temperature sensor has a normally closed switch that opens at about 90c. If one of the terminals was broken off, your Onan should have shutdown after it started. 

I am unable to test my memory and belief, but anyone with a multitester, can check me on this by disconnecting the wires and checking continuity across the terminals on the sensor. Also they could start the Onan and disconnect a wire to see if it shuts down. 

Funny coincidence, when I was in Marmaris I had a watermaker tech in the engine room who broke one of those terminals. I did not notice it until weeks later because he screwed the two wires to the remaining terminal. The Onan ran fine because what he did simulated a closed switch. If I would have had an overheat situation, I could have ruined the Onan because I had no working sensor. 

I learned several lessons on that one.  

CW Bill Rouse
Admiral, Texas Navy
Commander Emeritus
Amel School www.amelschool.com
720 Winnie St
Galveston Island, TX 77550
+1(832) 380-4970


On Jun 30, 2017 15:40, "svperegrinus@... [amelyachtowners]" <amelyachtowners@...> wrote:


Our sensor, marked F230 402-370 0013, was found failed (one of the wire terminals broken off) during an Onan inspection in Italy, and the part would have taken weeks for express delivery from Onan Netherlands.

Here in Marmaris, the part is available at the Onan shop for a "modest" $125. But I have two questions:

1.  If I install it myself, is there a need for a thermal paste or some other exotic procedure other than just screwing the new sensor where the old one was?

2.  How do you "test" such a sensor?  Obviously its absence has not been detected by the genset, which runs like a champ, so after installing the shiny new part, how do I even know if the new part is doing anything other than sitting pretty?

I think a functioning sensor is important as otherwise an overheating situation will not be detected and the motor will burn out and possibly cause a fire.

Thoughts?  Comments?  Thanks in advance!


SM2K N. 350 (2002)

Marmaris, Tk