I have a .21 motor in my inferno (just new) it is broken in and fitted with a temp gauge. It runs around 270 to 295`F. Is this tooo hot? What would be a normal running temp?

I've accidentally gotten motors that hot, and as long as you get it cooled down quickly, there is not much danger. Richen your high needle, or cut a bigger hole in the body. Also remember there is discrepancies between temp guns and loops. Hell, a friend of mine has the same gun I do, and his reads 3 degrees higher than mine. With all my motors, I've tried to keep them below 280, just as a rule. You can judge by sound too- if it sounds as if the motor is "cooking" or "sizzling", cool it down quickly, or shut it down immediately. Those sounds generally indicate that you've broken the 300 degree mark.
Hope that helps.

Matt

Thanks PHATKAT
I was a bit worried about the cooking part. So below 280 is good.

Yup.

Matt

put an egg on it... if you see smoke coming out within 5 minutes, you know its frying!!

i'm not sure what motor you have, but i think running constantly @ 280+ degrees fahrenheit can't be too good. you can actually smell the metal burning.

anyway, i was lucky enough to have don waller help me break in my ws72. the temp @ which you break in your motor is going to dictate how hot it will run. so, if you break it in cool, your engine will run better @ cooler temps. on the flip side, if you break in your motor hot, you'll have to run it hot to get it's max potential.

my c-5 ran best around @ 225 deg f. my ws72 runs best around @ 195 deg f. now the ws72 has had only about 1/3 gallon through it, and i run it pretty rich. even though its still pretty rich, it has a tremendous amount of power. i'm sure if i tune it and lean it out a bit, i'll really feel the power. right now, i'm trying to not overwork it until atleast i've gone through 1 full gallon. even then, i'll try not to let it get past 240 deg.

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Can agree. Went to a Club meet for Nitro on the weekend and they run these engines around 280 to 320. No probs and they do run better at these temps.

.

Newcastle NSW

I ran 4 gallons thru on a .12 picco at 220-230 F... Got 2 gallons at 250-260 F Depends on how long you want the motor to last.. ehheh