On Mon, 27 Feb 2006 00:49:23 -0500, "RCE" wrote:
One thing I've always feared about diesels is the very rare potential of a
"runaway". My wife's uncle was a vocational school diesel instructor and
told me of this condition whereby something goes wrong (I forget what) and
the diesel continues to increase revs until it basically self destructs. If
it happens, you have to quickly find a way to cut off the air supply or the
fuel before it goes "boom".

As I understand it, that can happen if the rings get badly worn to the
point where the engine is able to start running on residual crankcase
oil. Most of the 2 cycle Detroits are equipped with an emergency
shutdown device which is basically a spring loaded metal door which
closes off the air intake when activated. When we bought the boat,
the 671s in my Grand Banks had the shutdowns installed on the engines
but no remote cables for activating them. That was one of the many
upgrades that we added last year before heading north since the idea
of being up close and personal with a 3,000 lb runaway engine was not
too attractive.