STUGUTS_XY

Would anyone out there be able to set it straight for me, i am running a holley blue fuel pump feeding 650dp and running 7psi pressure.
The pump is plumbed from tank to reg to carb with no return at all,if i increase the pressure the bowls tent to flood {fuel runs out the top} even with the floats adjusted low,the engine runs and performs well.
The way the system is set up does not seem right ,this seem like it would be causing undue load on pump and shorting life of pump ????


TANK-------PUMP--------REG--------CARB

fomocoB

I have been running a same set-up for a number of years with no problems......Just make sure the pump is below the tank and your using a sump that the pump picks up out of.......these pumps do not like to pull....they like to push. So if your pick-up tube comes out the top of the tank you can be catching some air and hurting the flow(and the pump) with cavitation. hope this helps!
Bruce

STUGUTS_XY

Do you know what the requiried pressure is to be set at and do you why it floods the bowls if i take it over 8psi , i presume it is pushing needle off seat.

fomocoB

8lbs should not push it off the seat....what size line are you using? Steel needle/seat or rubber tip?

STUGUTS_XY

3/8 braided hose not sure of needle as i have never had bowls off.
When i adjusted floats i did at idle with side plugs out and adjusted till fuel just slightly started to drip out .

brenx

8psi will push past the needle and seat. You should be running 5 3/4psi. The fuel setup should work fine that way for many years. I ran the same setup for 5 years without an issue.

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XB Fairmont (street car) 11.07@123.02mph.

fomocoB

ck to make sure that there is no dirt,rust etc in fuel...that will play havoc with fuel control and also embed itself in a rubber(viton) needle and seat.....The problem with running to low of pressure is when you launch the car the fuel will stall in the lines.....you may be alright because of using 3/8 line...but using smaller line also will cause fuel starvation if the engine requires more volume...depends on the HP of engine and how hard you turn it. When was the last time you replaced fuel lines? Lines can build up crap on them....then when you go meesing with them the stuff flakes off in the fuel.....
Bruce

Dmax

I had the same problem with a 350 holley on a 302. Wouldn't do it all the time but every so often would flood and pump fuel out over the top of the carby. Changed the needle assembly, the bowl, etc, never helped. Sold the motor since and now got the Holley blue pump at the tank but I was told you need a return as the pressure build up would be significant at idle, and I'm running twin 660 centre squirts. I have no problems with that setup.

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