Paul Tomblin wrote:
In a previous article, "Private" said:
(and during) and clear the engine frequntly during any extended closed
throttle operation such as engine out practice and testing. IIRC the

I always thought "clearing the engine" was an old instructors tale, like
shock cooling.


Nope. The most likely time to foul plugs is when an engine is at idle or
very low power settings, which is why leaning during taxi is so popular. The
combustion process gets very dirty at low power settings. The fixed timing
is optimized for high rpms, so it's not optimal with the throttle back. Also,
combustion temperatures drop to the point where lead in the fuel is not
completely vaporised, which leads to deposits.

John Galban=====N4BQ (PA28-180)

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