Couldn't you just turn off the master switch so the hobbs stops, and
kept the engine running?

Hobbs usually runs on oil pressure. The master wouldn't kill it.
However, I got bitten by an airplane whose hobbs ran on the master. I
turned the master on to get clearances and such before starting the
motor, and noticed the hobbs clicking away with the engine off.

Jose
--
Get high on gasoline: fly an airplane.
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