Positve gnd vs Neg gnd fuel pump

[1939 P8 Deluxe]

1939 Plymouth P8 deluxe.  6v Positve ground.  

 

Can I use a Carter fuel pump specified for negative ground / just puttin the Neg on the Pos terminal and connecting Pos. To chassis?  I cant seem to find anything reliable on this topic.  

 

The fuel pump that I bought is Carter 4259BE. 

 

Thanks!

[31nash880]

Had to do this for a 31 nash. Fuel pump was insulated from the bracket so I could wire as needed.

[1939 P8 Deluxe]

Same fuel pump?

 

[Oldtech]

5 hours ago, 1939 P8 Deluxe said:

1939 Plymouth P8 deluxe.  6v Positve ground.  

 

Can I use a Carter fuel pump specified for negative ground / just puttin the Neg on the Pos terminal and connecting Pos. To chassis?  I cant seem to find anything reliable on this topic.  

 

The fuel pump that I bought is Carter 4259BE. 

 

Thanks!

Yes unless the pump has 2 leads and the case isn't connected to any of them you must make a mount that insulates the pump housing from the car and put the live ( neg) to the case so takes a bit of ingenuity.

Edited October 27, 2022 by Oldtech (see edit history)

[Lahti35]

16 hours ago, 1939 P8 Deluxe said:

1939 Plymouth P8 deluxe.  6v Positve ground.  

 

Can I use a Carter fuel pump specified for negative ground / just puttin the Neg on the Pos terminal and connecting Pos. To chassis?  I cant seem to find anything reliable on this topic.  

 

The fuel pump that I bought is Carter 4259BE. 

 

Thanks!

I would repair the mechanical pump, they're not complicated. Unless your fuel lines and tank are clean and your carb is in good working order an electric pump most likely won't help the car.

[1939 P8 Deluxe]

The mechanical pump was long gone by the time I acquired the car unfortunately. 

[jrbartlett]

You'd still be better off finding an original mechanical pump for the engine. Plymouths likely used a fairly common pump and someone on the Chrysler or Plymouth forums can probably tell you which one it is, or even supply one.  

[keithb7]

I run a stock mechanical pump and I have a 6v electric in my 1938 Plymouth. The electric pump is used to prime the fuel system after the car has been sitting a few weeks. Its much quicker than putting maximum load on the 6V battery for longer periods, cranking the engine over to activate the mechanical fuel pump. I also use the electric pump to give a good shot of gas if needed, pushing through any vapor lock that might occur. It’s great for that. It doesn’t happen often but when conditions are right it can happen. The electric pump works great. 
 

Other than these two examples, the stock mechanical pump is doing all the work.  I’ve rebuilt a few of the stock pumps. Its not hard. I have several spares for parts if I need them. They are not hard to find. Find an old crusty one for cheap. Rebuild it. 
 

My electric pump has two wires. The pump is isolated from its mounting bracket. Just hook it up to the positive ground system it’ll work great. Black wire to power source. Red wire to ground. I’m multiple years into using mine. Works great.  I have a sprung momentary switch feeding voltage to the electric pump. I doesn’t stay on unless I am holding the switch on.  Its safer that way. In the event of a fire or accident you don’t want the pump staying on, constantly pumping raw fuel into a fire. 
 

This one seen here is my 6V pump. 
 

 

Edited October 29, 2022 by keithb7 (see edit history)

[keithb7]

This one here is very similar. It will do just fine. 
 

https://www.ebay.com/itm/232368228294?epid=528692283&hash=item361a39c7c6:g:vb8AAOSwB0xdPku1

[1939 P8 Deluxe]

Great intel, thank you.  Life was keeping from the car for a bit- going to be back at it soon - much appreciated.  I'm excited to compare notes on this!