Lean will do it fast. Makes the pistons hot.

I'm pretty sure I have a bad gauge or gauge connection. The eng oil seem like it should have got a little burnt or darker color but still looks like honey. I'm going to put a temperature laser on the oil filter and a few other places to confirm.

Any chance you could just swap sensors between the engines? Or an easier check might be to swap the wire connections - you could probably fab up a couple of extensions from some wire and solderless terminals. If the other gauge starts reading high, you have isolated your problem to the sender. However, it's unusual for a sender to go bad like that. Laser temp gun might tell you something, but it can give a false reading as well. Maybe you could get a comparative reading between the two engines. Point it at each oil pan, and see if you get a significantly higher reading.

carb HP500..do these engines come with oil thermostats? if so, where are they located? I have good water temp, good oil pressure, just oi temp goes high quickly, other motors run cool oil temps??

did you ever find your high oil temp issue solution?? I am having the same issue with one of my HP500's

OLD thread... but having similar issue, if the oil t stat sticks closed can someone confirm the oil is not sent through the cooler ? & result in high oil temp?

Yes and yes, and if you remove it oil dead heads in the cooler. So you have to have a good functioning tstat in that housing.

x2.

ok, thanks guys... the t stat had some crud on it, I ordered a new one.. but may not have in time for the weekend , I did clean up the old one & it now expands in a pot of boiling water .. should get me by for now