want to convert to electric fuel pump on my 74 6x6

[geoargo]

If you really want to switch to a electric fuel pump which I'm done on a few machine due to diaphragm pumps failing. I would recommend a screw style pump like these.
Amazon.com: Mr. Gasket 42S Electric Fuel Pump: Automotive
The electric diaphragm pumps still fail like the vacuum ones.

I have been having problems with fuel starvation going uphill and backfiring going downhill on my 2003 Bigfoot. Would this be a suitable thing to try? I have always felt that the vacuum fuel pumps are not really up to the job,

[Canadian_Zuk]

I would like if someone can explain whats ment by adding a t fitting to return fuel to tank

He is talking about having a return line to the tank. The stock pump only delivers 1.5 psi, this low pressure makes it easy for the float needle to stop the flow of fuel into the carb bowl. The aftermarket electric fuel pumps put out up to 3-5psi, this slightly higher pressue "may" be enough to overcome the needle pressure allowing excess fuel into the carb and flooding your motor. This can actually be a very serious problem if youe sitting parked with the ignition on, after the carb bowl fills up the excess fuel will start to spill down the carb throat into your motor. This can lead to a hydro lock when you try to start the motor again or the fuel will simply wash past the rings and into your crank case. If you run the motor with a crank case full of fuel you won't be happy.

The solution to this potential problem is to install a return fuel line with a 1.5 PSI check valve using a T fitting. Once the upstream fuel line pressue reaches 1.5 PSI, the excess fuel is bled off through the check valve and back to the fuel tank through a return line.

[Canadian_Zuk]

I have been having problems with fuel starvation going uphill and backfiring going downhill on my 2003 Bigfoot. Would this be a suitable thing to try? I have always felt that the vacuum fuel pumps are not really up to the job,

Sounds like your a perfect candidate for it from your description. Backfiring is also a sign of a lean mixture (lack of fuel).

[geoargo]

Sounds like your a perfect candidate for it from your description. Backfiring is also a sign of a lean mixture (lack of fuel).

Thanks

So it sounds like I also need to install a T fitting with check valve and return line as you describe above if I am going to use this unit becasue of the higher pressure this puts out. Wouldn't that require a long fuel line all the way back to the fuel tank plus some modification to the fuel tank to get the retun line into it?

[Canadian_Zuk]

Thanks

So it sounds like I also need to install a T fitting with check valve and return line as you describe above if I am going to use this unit becasue of the higher pressure this puts out. Wouldn't that require a long fuel line all the way back to the fuel tank plus some modification to the fuel tank to get the retun line into it?

A return line from the engine compartment would be most ideal but you can just run the T fitting from near the fuel pump at the rear of the machine into the tank, as long as you splice into the fuel line upstream of the electric pump a few inches you'll be fine.

Has you machine always acted this way or is this a recent problem? I would start by changing out the rubber fuel lines and either replace or service the diaphram vacuum pump if this is something that started recently. Fuel lines deteriorate over time, if they are old and original they may be part of your problem. I also like to add a see through fuel filter just before the carb on everything I own, you would be surprised at the amount of rubber particles I see sometimes.

[geoargo]

A return line from the engine compartment would be most ideal but you can just run the T fitting from near the fuel pump at the rear of the machine into the tank, as long as you splice into the fuel line upstream of the electric pump a few inches you'll be fine.

Has you machine always acted this way or is this a recent problem? I would start by changing out the rubber fuel lines and either replace or service the diaphram vacuum pump if this is something that started recently. Fuel lines deteriorate over time, if they are old and original they may be part of your problem. I also like to add a see through fuel filter just before the carb on everything I own, you would be surprised at the amount of rubber particles I see sometimes.

Thanks - forgive my ignorance and additional questions but I want to get this right.

The fuel line on the Argo comes out of the tank under the seat and then is tucked under the body until it enters the engine compartment so I can't see where I would put the fuel pump except in the engine compartment. The vacuum pump is, of course, mounted right on the engine and is just downstream of the fuel filter. Would I not need to put this one in a similar spot? I am also confused why you would put the T fitting UPstream of the pump - surely it would be DOWNstream as that is where the pressure would be produced isn't it? (I am interpreting UP as closer to the fuel tank and DOWN as closer to the carb - is this wrong?)

In order to get the fuel back into the fuel tank wouldn't I need to drill a small hole in the tank to put the return hose through?

This behaviour has been on and off for a couple of years. Last year I replaced all the fuel lines and had the carb rebuilt and that seemed to stop it for a while but it is back to its old behaviour again now. I had a new diaphragm fuel pump about 3 years ago. Probably driven about 15 hours since the carb rebuild. Machine has just over 300 hours on it in total.

Thanks for taking the time to answer these questions.

[Canadian_Zuk]

I'd bet your diaphram pump is dried out again from sitting.

Upstream of the fuel pump means closer to the motor. Where the fuel line comes out of the tank behind the seat is where I cut the line and installed my electric fuel pump on my Vangurad, I also have my battery relocated here as well. I mounted the fuel pump to my battery box so it's just under the back edge of the seat. Eletcric pumps are designed to push fuel, diaphram pumps pull fuel.

[geoargo]

Thanks again. So if the pump is pushing fuel rather than pulling it, given that the fuel line comes out of the top of the fuel tank, how does that work?

In order to get the fuel back into the fuel tank from the T fitting return wouldn't I need to drill a small hole in the tank to put the return hose through?

[ARGOJIM]

I would assume the backfire going down hill is an exhaust leak.