I was using it on a profile plane. First flight usually started out having to adjust the needle. Each flight after it was adjust the nedle until about the third or fourth flight then it would stabilize. I crock potted it to get rid of the coating. Now it is fuel up, start engine and fly. Unless big temp change in weather it is now consistent. This is the LA .40 that used to be blue. Maybe it was just an oddball engine. My LA .46 which is still blue seems to be consistant in the P-39 which is partially cowled. Both engines are box stock internally.