FastEddieB wrote: As an aside, I only recall getting carb ice once in my flying career. I was flying some students around on short flights in a J3 Cub. South Florida, so not cold at all. On one flight, I got the impression the throttle was creeping. I had to keep nudging it forward to get the same rpm. When I finally had full throttle and still had lowered rpm and performance, carb ice dawned on me and I applied carb heat. The engine stumbled, then died momentarily before coming back. Whew! On landing, there was actually frost on the outside of the carb and it was quite cold to the touch.
My most memorable carb ice incident was also in a J3. The day was April 1st, 2006. I had just purchased the airplane in southwestern Michigan. The temps that day were right around the freezing level with snow showers. It was my first flight in a J3, and I was all bundled up for the cold, and strapped snuggly in the back seat with a lap belt and shoulder harnesses. Like you I was flying along and the RPM would drop off a little bit. Being new to the airplane I thought the throttle was working its way back, so I kept pushing it forward a little at a time. Flying along all fat dumb and happy the engine coughed, and I reached for carb heat. The only problem was I couldn't reach the carb heat. I finally hooked the knob with the sole of my shoe and pulled on carb heat. The RPM dropped of a little more and the engine ran rough for a few seconds and then smoothed out. When I turned the carb heat off the engine RPM increased by about 200.