For the past 10 years I have been plagued with a Yanmar 100 HP engine
that does not always shut down immediately when the red stop button is
pressed. It can take up to 40 seconds to stop, requiring you to hold the
button throughout this time. Amel sent a modification kit to incorporate
a relay to help keep the volts up on the stop circuit but it did not
help. After years of checking every cable, and incidentally meeting
several non Amel owners with the same engine and same problem, I
concluded that the problem _may_ lie with what looks like a surge
prevention resistor in the wire that goes to the shut off unit located
inside the fuel pump, or the shut off valve itself.

I contacted Yanmar for a new resistor, but in keeping with marine trade
piracy it was of course only available with the complete shut down
assembly at a cost of around £500! A bit like trying to get a new rubber
key cover for the control panel which used to only be available if you
bought an entire new key switch!

Anyway for £5 I have found a compromise work around using two 12V
relays. Now I just need to momentarily press the stop button and the
engine will shut down in its own time. Turning the ignition off resets
the system. Not ideal in a fire situation, but a big improvement.

If anyone would like details on how to wire this up, let me know and I
will email the details.

Ian Shepherd SM 414 (2003) Crusader - Aegean