On Sat, 15 Sep 2007 17:41:58 -0700, JR North
wrote:

Make sure the idle speed is set correctly and it's not idling fast or
sticking. This, combined with a hot shutdown will cause extended run-on.
Just hot shutdown by itself may cause some minor run-on.
JR

aieo wrote:
Today for the first time all summer my 4.3L MerCruiser had a long "run-on"
after engine contact was closed...what could cause this?


I had this a couple times long ago - had to put the car in gear to
stop the engine.
As I recall, carbon buildup on the valves can cause the deiseling,
aside from why gas is getting in there.
Damned if I can recall what I did to fix it, but carbon deposits
is one thing to look for. A good WOT run or gas additive might
help on that score.
The carbon itself can get there by oil down the guides or ring blowby.

--Vic