Originally Posted by Uncle Bob
The higher in elevation the higher the temp must get to boil the water out, the lower the elevation the lower the temp.
Well Bob, since you don't seem to grasp the basic relationship of water vapor pressure vs atmospheric pressure, I believe I will take the balance of your advice with a grain of salt.
Since you are running the OEM cooling system, run it as hard as you like. That engine was made to stand in one place, running a constant full load. People cold start B&S engines & run them against the governor as soon as they can every day. A genset spins to 3600 as soon as it fires, and often gets loaded before the choke can be opened.
The splash lubricated Briggs design is pretty tough. Try to use oil with some Zinc (ZDDP) in it. Change it often. I did warranty repairs on B&S engines, and new engines left with 15W40 diesel oil in the crankcase.
Never had one come back, and some of them were mounted on snowblowers. 110v electric start at -20f & wide open throttle as soon as possible.