On Mon, 29 Aug 2005 06:56:01 -0500, "mbremer216"
wrote:

Cherokee w/Lycoming 0360-A4A

Normal flight in all respects. When shutting down, pulled throttle to idle
and mix to idle cut-off. Engine took just a little longer than normal to
run down. Just as it should have stopped, it caught and actually ran
backward for a couple of turns before stopping.

Any ideas as to why?

Quite common with engines that have timing well in advance of TDC.
Usually caused by plugs that are fouled with carbon, which stays hot
and causes detonation under compression. Called "dieseling."

You can lessen the chances of it happening by revving the engine up
just before you cut the fuel mixture. Running backwards isn't good
for the engine -- and it can play hell with vacuum pumps, as the vanes
are designed to turn in one direction only. Same problem in cars and
outboard engines with water pumps.


Thanks

Mike