Two fuel pumps

[Oldfireguy]

I bought a mechanical fuel pump for my '59 CJ5 through Ebay. I think it failed already. That was confirmed when I hooked up an electric model. The mechanical unit is still on the motor with the pressure going through it from the electric unit. Question: would too much pressure develop with two units hooked up in series?

[bmorgil]

I bought a mechanical fuel pump for my '59 CJ5 through Ebay. I think it failed already. That was confirmed when I hooked up an electric model. The mechanical unit is still on the motor with the pressure going through it from the electric unit. Question: would too much pressure develop with two units hooked up in series?

Oldfireguy, yes you could build too much pressure from the Electric pump you should regulate it. This is not why you should not do this however. Eventually the diaphragm in the mechanical pump will fail. When it does, fuel will flow into the engine crankcase filling it with gas. If you want to run an electric pump remove the mechanical unit and use a fuel pump block off plate to cover the hole, and add a regulator.

[Oldfireguy]

Thank you. The electric unit has its own switch, so I might shut it off after starting. For some reason the mechanical unit works again.