I would like to understand the priming pump in more detail. My Detroit Manual indicates that the fuel filter is between the tank and the fuel pump. That means that the filter is normally under vacuum as the fuel pump pulls fuel from the tank and on through the filter. Is it correct to assume that all the fuel passes through the priming pump? If that is the case, then when one pumps the priming pump it will pressurize the fuel downstream of it and push the fuel toward the engine. For fuel to flow it must displace air or fuel. If the cap is off the filter then fuel would be pumped into the filter. I have tried that, and I am able to see the fuel level rise in the filter.
What happens if the fuel pump has pulled air into the lines between the filter and the pump, or even moved air past the pump and onward to the injector? Is there a place you let this air escape as you pump the priming pump? Thanks to anyone that knows..... Russ
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