Question regarding wiring up a carter electric fuel pump

[findinghomer]

OK, let me ask a dumber question. If his motor does not have the machining for a mechanical fuel pump, why does it not have the wiring for an electric fuel pump?

Bc I had to repower, and I upgraded to a vortec engine, And unfortunately it's not machined for a mechanical fuel pump

 

[findinghomer]

It may help understand how to wire the fuel pump if you understand why it's wired the way it is.

The fuel pump should receive power only under 2 conditions.

1. When the engine is actively cranking over, but has not yet started. In this condition, the fuel pump gets power from the bypass terminal on the starter solenoid.

2. When the engine has sufficient oil pressure to close the oil pressure switch. Under this condition, when there is no oil pressure, the oil pressure switch is open, and not sending power to the pump. When there is sufficient oil pressure, the switch closes and sends power to the fuel pump.

And that's it, under no other condition should the fuel pump be receiving power.

Yes I understand that, I was confused about how the starter doesn't get 12v back feed from the purple wire, When I'm done turning the key, and it's now in the run position.

 

[Chris1956]

Gee, a lot of folks likely do the upgrade like you. Can you get a new wiring harness for your motor with the electric fuel pump wiring?

 

[Scott Danforth]

wiring harnesses are a few hundred dollars to a few thousand. the wiring needed to add a relay and oil pressure switch and the fuel pump is under $100

while you can buy a harness.....why

 

[findinghomer]

Gee, a lot of folks likely do the upgrade like you. Can you get a new wiring harness for your motor with the electric fuel pump wiring?

Yeah it's really not that big of a deal, But before I proceeded I just wanted to run it by the iboats experts. I just didn't see how it doesn't back feed to the starter, but somebody also gave me a tip to put a diode on that line.

 

[findinghomer]

Your 2 pole switch will work if you wire 86 to the starter (or yel/red) and 1 side of the OP switch. Other side of the switch goes to purple. 30 gets 12v, and 87 goes to fuel pump.

Hey Mike, when you say go to the starter, You mean that extra terminal on the starter right? The small one? Also can grab the purple wire , in the back of the engine where it goes to the coil for my ignition?