[capta]

Every diesel generator I've ever had installed on a boat (or shoreside for that matter) has a high temp shut down that operates in conjunction with the temp gauge sender. Shouldn't cost more than a few bucks to install a normally closed sender (for whatever temp you desire) at the same point that your present temp sender is located and run it to the fuel solenoid power wiring. Engine gets hot, sender opens, cuts power to the fuel solenoid and Bob's your uncle; your gene goes to sleep. Easy, cheap and reliable.

 

[capta]

EGT probe too? I want to save a burned hose and muffler.

So get a 200 degree sender. Generators are constant speed engines that rarely vary a few degrees in operating temp while operating, so if the standard operating temp is 180, 200 should do the trick before any damage occurs. What's an EGT probe?