Dual Fuel Pump Question

Is there any problem with running two fuel pumps ? One being a mechanical -- the other being electric ?
I run a stock mechanical pump now with no real issues -- other than when my car sits for to long ( I know, I know -- drive it more !! )
If it does sit for to long -- it takes forever to get fuel up to the carb to start it up.....so I was thinking about installing an electrical pump back by my fuel tank -- and only using it once in a while as a primer to get fuel up to the front end quicker -- then crank up and turn the electrical one back off ....

Anyway -- does anyone see any reasons NOT to do this ?
Thanks in advance

 

certain electric pumps can't be pumped through. had a problem with a 41 cadillac thought it was vapor lock. removed the frozen electric pump problem went away.

 

Buy a french flathead fuel pump. It has a primer on it. Just pump it by hand if it's been sitting too long.,

 

Could you put a rubber "bulb" in between the tank and the fuel pump like they use on outboard motors?

 

Seen it plenty on collector cars that sit for long periods.

Put the electric pump close to the tank and push through your mechanical pump. You'll have no trouble.

Just turn the electric on for a few seconds, hit the key and go.

Shawn

 

i've use both a stock mechanical and an electric fuel pump on everything i build now. i switch the electric on for starting as you said.

 

I have a Carter electric pump and my AC Delco fuel pump pumps fine through the Carter. I use the Carter to prime if needed, or a backup if the AC pump fails.

Note: do not use the electric pump to pump through a mechanical pump that has failed. Design your system so you can use either one at a time.

 

Does a mechanical pump just FAIL and it is done -- or will it actually show "signs" of it going to fail -- like low fuel delivery or anything ?
Thanks

 

On my ol Charger, if its sat more than a week, I prime the carb before starting so I don't have to crank so much. I squirt some gas down the Holley vent tube into the bowl, enough until the accelerator pump will squirt, then start.

I had an electric pump by the tank feeding the mech pump, that worked great for priming, but took it off as the car wasn't fast enough to need it, and I've learned an electric pump will feed a leak real well and I really hate fires. Once I had a stuck carb float while trying to start, happens easy enough with a Holley, and that elec pump made a fountain of gas shooting straight up out the bowl vent about 6", really lucky it didn't light! If the diaphragm in the mech pump fails, gas will go into the crankcase, and if there is an elec pump feeding it, a lot more gas will go in, plus maybe enough gas will still make it to the carb to keep it running so you don't know its also going into the oil. So I don't recommend an electric pump on a carbed car if you don't really need it.

 

The new fuels are very hard on the older mechanical fuel pump diaphragms. If you pump through a pump with a ruptured diaphragm it can fill the crankcase with gasoline with no sign of a leak. It dilutes the oil and will kill a new engine in a hurry. I ruined a new engine just because of a recurring dirt in the inlet problem never thinking that the flooding fuel was going into the crankcase. I replaced the fuel tank only to find out that I needed the fresh 396 to be rebuilt AGAIN!.

I start my engine periodically just to keep fuel in the carbs. If it doesn't get started in a month then I pull the aircleaner and give it a shot of starting fluid. All my cars start instantly even with points. A battery tender keeps the battery up so 2 pumps of the accelerator and a bump of the starter button and she's running. Every other week seems to do it.

 

A mechanical pump can have a broken spring or a number of other mechanical failures. A valve can leak due to wear or contamination. Worst case, with most engines/pumps a leaking diaphragm will leak fuel into the crankcase oil, and in some cases onto the outside of the engine..

Unless it is outright leaking, a failing pump will generally work ok at lower speeds and loads, but due to reduced delivery volume/pressure won't allow sustained running at higher looads/speeds.

 

the only thing I would be worried about is the diaphram in the mechanical pump busting, and gas would be all over.... I only run an electric on mine bypassing the mechanical. 230 flathead