Q: In my pilot club meeting last month, a pilot complained of spark plug fouling before takeoff in our Grumman Cheetah with 150-hp Lycoming. I suggested that after starting the engine, and before taxiing, she lean the mixture, keep it lean while taxiing and put on full rich for run-up. However, if there is a delay — say she’s fourth in a line of four airplanes for takeoff — she should lean until cleared for takeoff.
Another member cautioned that leaning while taxiing can burn up a cylinder. I say that while taxiing the engine rpm is too low for a lean mixture to burn a cylinder. My brother says not leaning may, in addition to fouling plugs, cause a valve to burn or other damage.
What say you?
FRANK DE LA PUENTE, Salem, Ore.