Savage 25. Using temp meter what is in pic. Run for 2-3 min big temp changes in between runs. Run 100 yards and check. Book says for Nitro-star S-25 motor optimum 210 to 275 max. Was adjusting to keep in range. Was adjusting carb all the time. Drove myself nuts. Finally got MAD. Let it run and blow it up. Running it hot and not caring about temps engine never did it on final carb setting got over 290. Would have rich it up it over 300. If anything ,I was trying to run it too rich to keep it cool. (Novice) Every run up and down my road changed temps. Got tired of 1/8 inch settings. My mind said this is bull. After setting carb so not over 300, have not had to reset anything. Hit the max of 290 on temp and never looked back. Dog until warmed up a bit, but runs good after 200. Run to warm after start maybe 50 yards and back. Altitude 3280, humidty about 30 to 50, air temp between 80-90. Tuning carb for motor to run just under 300 made play without adjustments great from 60 air temp and up. Was trying to do good, but maybe being safe is not the real answer. I got into r/c because I cannot afford sand racing with jeep anymore. Get outside the box. Tech is fine, but don't get tied down with specs. Specs only sell parts, do what is right for the pocket book. After 14 years my jeep is still strong. Just cannot afford the fuel it takes to get to races. Maybe the old hold your hand on head is better than the temp guage? Lots of variation due to skin thickness, and mental determination. NO FEAR, up to a certain point.