electric fuel pump on carb'd engine...

[sidriptide]

heres the basics......
'glass CJ5, ford 5.0L, Carter AFB carb, 4-spd trans.. (yeah its a hotrod.. )

i just eliminated the mechanical fuel pump for a totally new fuel system. all braided -6 aeroquip line and fittings. summit/holley electric pump rated for 14 psi, adjustable regulator 4 to 9 psi, set at 4.5 psi till i get into tuning the system. i had "assumed" the pump was somehow regulated internally to stop running at 14 psi and start as the demand required.. turns out not to be the case. it just constantly runs and the regulator holds the pressure back.. i am guessing that the pump is more of a displacement pump than centrifugal since it self-primed the system when i started it. but when i shut it off it drops to zero psi so it obviously back flushes.. this is confusing me whether i should run a system with a return line to keep the pump from over-heating because it is constantly running with little actual fuel flow... i was told i didnt need to do that.
relearning this old-tech carb stuff is fun, but just as confusing as some of the new-tech out there as well......

 

[5-90]

Does your regulator not have a return line? Most do.

Since electric fuel pumps tend to be of the "vane" type (some "gerotor" types are out there) - which /is/ a "positive displacement" type - you'll want to have a means for the overpressure to return to the tank. Most carb setups end up running around 4-6psig, so that could be an issue with your 14psig pump (you'll accelerate vane wear.)

Bear in mind a couple of things:

What happens when you ASSUME? It makes an ASS of U and ME (true enough...)

Assumption is the mother of all foul-ups (/very/ true!)

Don't forget your RTFM interface - I know it goes against "guy rules," but I'd rather break a rule than my wallet any day!

 

[sidriptide]

i guess i'm second-guessing the advice i got in the begining really.. i was told by a few people the pump would shut-off and i had no need for a return... didnt seem right or wrong really since it is a low-pressure system and i've never dealt with a system like this... my regulator does have 2 outlet ports, one of which i plugged with a plug that came with it...