I have a 6 horsepower Briggs & Stratton Engine on my push mower that I have been using since the spring of 1998. I have read on a few boards where people have taken temps of the oil and it has been between 220 too 240 degrees. The Briggs tech guy said that oil temps of 180 to 185 degrees are the desired temps.
For the last 2 years I have been running 1 ounce of auto-rx in the oil on this mower, yesterday I used the mower for 1 hour in 90 degree weather and when I was done I took a temperature reading with an infrared gun by aiming it down the oil fill hole into the oil. The temperature I got was 175 degrees, proof that auto-rx cleans and is letting oil get everywhere inside this small engine.
Remember oil not only lubricates but it cools, it is hard for oil to lubricate through crud and deposits in your engine.
