"Roger Long" wrote in message
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[...]
I had an idea today which worked well and I wonder if anyone sees a
downside. I always operate our 172 N on the ground leaned to the max.
Instead of using the brakes this morning, I just leaned some more until
the
engine sagged and controlled my speed that way.

I'm surprised that taxiing with the mixture leaned you have any trouble with
plug fouling at all. Have you brought the issue up with the mechanic(s) who
maintains the plane?

In my plane, with a Lycoming 540 engine, I get plug fouling if I don't lean
during taxi. But by keeping the engine leaned out during taxi, I have no
trouble at all with fouling, and I can still use the throttle to adjust
power. There's no need to keep the RPM above 1000 in order to prevent
fouling.

Since you're already leaning, I don't see why you'd need to also keep the
RPM above 1000. The leaning alone ought to take care of the issue. If it
doesn't, it seems as though there might be some adjustment needed. The 172N
is carbureted, right? Maybe the idle jet is set too rich?

In any case, if the mechanics say everything's set perfectly, sure sounds
like a winner solution. At low power settings, there's nothing you're going
to harm by leaning, and as you've found, it's a fine way to limit engine
power. Just don't accidently shut off the engine; that sure can be
embarassing.

Pete