Gentlemen, I have an interesting one for you. My C-model has a C-85 and a digital EGT gauge. I just got it out of annual and today was the second time I have flown it. Bring it home from the annual (two hour flight) she was running EGT of about 1238 at full rich. (In the past at anything above 1240 she has started to miss because she too lean.) The AP said he advanced the timing on one of the mags because they were both the same. (Sorry don't remember what he set them at.) I took it up today, for my flight review, to an airport about an hour away and she creep back up to about 1240. In the afternoon with air temps in the low 90's, on the way back she was under 700. All these readings are full rich. I normally lean because I fly above 9,000 msl, but with temps so close to max I didn't.
Any ideas why she would change 500+ degrees in a few hours? On the ground I checked the mixture and cab-heat both OK. Richard NC99904
