"Wayne.B" wrote in message
...
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.


That was it. Running on it's own oil supply.

I had one educating experience with one of the Volvos on the Navigator the
first year I had it. We pulled into Indian River Marina in Delaware to
escape a heavy thunderstorm and I could not shut down one of the engines. It
sat idling for an hour while a Volvo tech in PA tried to walk me through it.
The problem was that every time I went into the engine room to do whatever
he was telling me, I couldn't hear him on the cell phone anymore. Finally
found the mechanical lever to manually shut off the fuel supply at the
engine and noted it's location, however the real problem was a tripped
"reset-able" fuse on the control box. Reset it and the solenoid that shuts
the fuel off now worked again with the keyswitch.

RCE