G.R. Patterson III wrote:
: I frequently pull the prop through four times to check compression. This also makes
: it slightly easier to start in Winter by breaking the gummy oil bond that tends to
: form between the rings and cylinder walls.
: Make sure the mags are off and mixture at lean cutoff. Pull the prop in the direction
: it normally turns. Stay out of the plane of the prop. My prop is indexed to stop
: straight up and down. When I pull the prop through, I pull the lower blade up.
:

I generally pull my Lycoming O-360 through at least 4 blades (all compression
strokes) to verify that I've got the adequate and roughly equal on all strokes. I got
in the habit of doing this after a recent top overhaul, to check on the status of the
break-in.

In addition to the mags being switched off, mixture leaned, and never primed,
I *always* pull it through as if I were hand-propping it (expecting it to fire off).
If you ever once pull it through without that thought, you're looking to have a new
nickname.

That said, it probably doesn't do much for the engine, good or bad. In cold
weather, just nudging the prop would do the same "loosening" as pulling it through a
few blades. If your oil truly is that gummy, though, better rethink your oil-changing
invervals...

FWIW,
-Cory

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