OK, I misread the OP's problem... And as a result of reading the other
responses I now understand... I also will be redrawing the propane
solenoid electrical on my boat as a result, keeping the mechanical
timer safety switch and adding a self latching relay...

The issue is momentary loss of power that interrupts propane flow which
then comes back on and allows the propane to flow again, with no pilot
light as a result of the interruption..

What I will now do is add a relay in the solenoid's +12v line... This
will be a self latching relay using a normally open contact to keep the
relay powered once it is actuated... When the 12V is interrupted the
relay drops out (opens all contacts) and will not pull in (close the
contacts) until the operator presses the START button again...
This is standard on most power machinery, table saws, etc., where you
do not want the saw suddenly starting as you are changing the blade and
your helper sees the power cord is unplugged and "helpfully" sticks the
plug back in the wall...
Any ABYC electrician should know how to add a self latching relay to
your propane solenoid circuit...


denny