"Roger Long" wrote

I can't remember where I "learned" it but I always thought 1800 RPM was the
limit for ground running leaned to clear plugs. I had a really bad one
yesterday with 250 RPM drop. I taxied back to the shop and they said to try
full throttle before pulling the plugs.

It worked but running the engine full power (near sea level) while leaned
for best power and peak EGT with minimum airflow for the minute it took
seems pretty abusive to me. Maybe you can get away with it because the
CHT's have not yet risen to max.

Any thoughts? What were you taught?

I was tought the full-power tactic. But what I found out empirically
was that leaning like crazy for all ground ops (to the point the
engine will barely run) has so far prevented the mag drop problem from
occurring again. I posted about this within the past few months and
found that others use similar procedures.

Jim Rosinski