This is an old thread, but I am trying to understand how this pump works a little better.

How often should the plunger be moving in the pump? Everytime the coil fires?

While the engine is running does the pump not cycle if the carbs have adequate fuel in the bowls? Or does it run continuously and have a pressure bypass within the pump?

 

The pump is getting supplied with pulses of power so long as the engine is running. The number times the plunger moves is dependent on how fast the engine is consuming the fuel. If it's running slow, the fuel pump will come to a stop due to back pressure from the carburetors. There is no bypass or over-flow passage way for the fuel to go.

 

Thanks for the reply. Jim shot me a message and explained that the fuel pressure keeps the plunger pushed in which keeps the contacts open. They won't close and fire again until the fuel pressure is relieved by consumption. That was the part I couldn't figure out. I pulled the carbs off last night and I'm gonna go through them and make sure everything is clean.