RE: CEN Matrix 1/8th scale
Double check your temp with a different temp gun. I have seen temp guns and on board systems be as far off as 70 deg.
You shouldn't tune your engine by temperature anyway. You should use temperature as a reference point for tuning.
Some reasons an engine will run hot and seem rich.
1. Engines will run hotter than normal when not fully broken in.
2. A lean bottom end will make your engine run hot while the top end is rich. (In some instances the bottom end may be so lean that it feels rich) Always look for a good amount of smoke to come out of the pipe when exiting a corner.
3. A rich bottom end will make your engine run hot and not have much power on the bottom.
4. A bound drive train will make your engine run hot and seem to not have much power.
5. Running in grass will make your engine run hotter than normal.
I hope one of these things fixes your problem if not I will try to think of some more.
Good rules of thumb for tuning without a temperature sensor.
MAKE SMALL 1 HOUR ADJUSTMENTS AT A TIME. ( think of the needles like a clock and adjust them in 1 hour steps.)
1. never tune a cold engine.
2. start out with stock setting and tune from there. (If the stock setting are to lean for your area then turn you needles out 1/2 turn.)
3. Get your top end set first.
4.Dab a little spit or water on the cooling head. it should evaporate in about 3 seconds. If it sizzles or boils it is to hot.
5. setting the bottom end. run your car to clear out the engine. bring the car in and listen for the idle to drop. this should take about 8 seconds. (some will say longer but I feel this is a safe area to be in. I usually tune mine to drop in about 6 1/2 to 7 seconds, Meaning I like the bottom end a little rich.)
6. keep your idle up just enough to make the engine idle after the drop. A high idle will make the engine run hotter.
7. Remember when you lean the top end the effects are also the same for the bottom end but with less of the effect. The same thing for richen up the top end.
8. changes in the bottom needle also effect the hot needle. (very slightly though) Most wont notice it.