Engine issue in cold temp

[Hockeystud87]

Went flying today and it was chilly out around 32 degrees at the runway. I did my normal run up and waited till the plane was warm having little issue. My carb sensor was showing just around 10C (50F). My carb sensor has a yellow arch between +/- 10C. Which I think signifies the spread in which there needs to be consideration for icing.

As I took off the engine had more vibration than usual. It didn't sound rougher just little more vibration. We did a few patterns and I noticed quickly that the carb sensor was showing an average of 4C. When pulling carb heat it would move again back towards 10C.

We decided to fly off to the next airport and along the trip it was showing 0C and the engine was beginning to sound rougher. I pull carb heat as I know the signs of carb icing. The engine had a little dip in RPM but my carb temps did not rise much past 3C-5C. The increase in temps was not impressive.

The plane gave a small hiccup and I turned around and headed back. As I was pulling carb heat on and off as we flew it was again not increasing carb temps by a considerable amount. It was dropping RPMS tho. At one point I had carb heat half open, then when I pulled it full open the engine gave a cough.

Can all this be attributed to just flying in too cold of weather?
Was there a upgrade on the carb heat that my old 92 doesn't have?

[rv9ralph]

What engine are you running? Which model Kitfox?

Ralph

[Hockeystud87]

Model 4 Speedster with a 912ul. With the carb heat.

[Slyfox]

out of 14 years with my kitfox between the 912ul and uls engine. I've put about 1600 hrs on the ul and about 500 uls engine. I've flown in the most ekk weather from about 20 degrees all the way up to summer at 104 degrees. have flown in a full blown snow storm (still vfr) you name it. if it was vfr, I flew, never, never have I had ice problems in the carbs. sorry don't buy it. No I do not have carb heat on my airplane. always flew with the little K and N filters.

[Shadowrider]

Not familiar with a Rotax, but carb heat enriches mixture. Any chance you are rich and adding carb heat made it rich stumble?

[Slyfox]

not saying this is your problem. but with all the carb float problems out there, have you weighed your floats. 3 grams a float is a good float. also have you checked to make sure your choke is ok, is it returning after you use it.