If stat was stuck open, he wouldn't be running hotter.
It'd take longer heat up.

Running hot, lower pressure than norm. Restricted/lack of flow will cause both of those conditions

Replaced housing and impeller and put it in water on the trailer. pressure is a little better but still about half of what the other motor is running

please re read the post .. it clearly will stay open if its above opening point and will not close till it cools down , so if its not getting water it will stay open till it gets water as i stated ,,,and while its open youre water pressure will likely be lower due to no restriction ,, and if theres little water flowing it wont take long to heat up open or closed ,, lol

It's been back and forth if that will cause a problem so you're suggesting a thermostat?

take youre inlet hose that feeds the block off and start the motor ... see how much water pumps to the block .. only run for a few secs youll know right away if youre moving water .. if you think it could be thermastat .remove it . takes a sec run it see if it over heats , two very simple things you can do to try to narrow youre problem down .. good luck i run no stat in my engines .. but have oil stat to regulate oil temps ..

I had a similar issue last week with low water pressure and high heat. I pulled the thermostat and replaced it, flushed it, removed the circulator pump and it was fine, raw water pump removed it and rebuilt it, pulled risers etc, etc, After stepping back a day or two I went back and disconnected every hose and flushed them again and I got half of a impellor blade out of a hose that must have been from the previous owner because all of my impellor blades were in tact. Problem solved. It was very frustrating. Good Luck.

Ended up having some rocks and trash on the line gong to the cooler on the top of the bellhousing now running 4500 rpm or more its at 35pounds of pressure

Glad you found the culprit!!

35 pds is high be carefull

been through this....same motors ....thousands later, so back flush your cooling. Believe me , there is crap inside one or all of your coolers. Also, check your risers. My guess is that they are o.k. as your pressure is low. Mine was opposite , way too high.