oil gets suucked into the ign. switch via the vacuum line to the shutoof valve. when it goes bad its usally the diaphram has a rip or leak and lets oil past it. then it gets sucked through to the switch then the pump

Matt,

I converted a 190D I had to the parallel GP. It worked great and started in about 10 seconds where it was 30+ seconds with the old loop plugs. I still had the "Gorilla Knob" but no glowing in the GP indicator holes. I replaced the resistor wire in the GP indicator with a copper shunt and remover the box resistor to get the full 12 volts to the parallel GP.

I always wondered why MB used the resistor wires between the GP or the resistor box in the 190D and wasted all that energy. It appears that the loop GP were originally made for a 6 volt system but why weren't the loop plugs changed to ones that operate on 12 volts instead of using the resistors to drop the voltage?

P E H