View Full Version : Fuel Pressure
car62
03-20-2016, 12:27 AM
i have a 358 engine, 650 carb, 110 octane race gas, 11.3:1 compression, have had carb rebuilt 3 times by 3 different builders with same results...hard to start, fuel starts pouring out vent, loads up each lap in race and smells of raw fuel, i changed fuel pump,even borrowed a known good carb and got same results...someone suggested to use a fuel pressure regulator, what kind of pressure should i be looking for? currecnt carb is a Quickfuel Technologies SS650 circle track carb with 74 and 75 jets, and high flow 6.5 power valves
r3tracing
03-20-2016, 05:55 AM
5 to 6 lbs on gas should work fine
JustAddDirt
03-21-2016, 10:58 AM
I believe r3tracing is on the right track.
What is the fuel pressure?
5-6-7 range is good for gas, you go over that and it will blow past needle and seat and you will experience problems you seem to be having.
is it a dual line carb or a single line?
what kind of fuel pump do you have?
car62
03-21-2016, 04:19 PM
its a single line 6-an from pump to fuel log where it Y's off and goes to each bowl, just the standard chrome edelbrock fuel pump
JustAddDirt
03-22-2016, 10:47 AM
Do you have a fuel pressure gauge on it?
pump may be a 7, 9 or a 13 psi. never going to know without a gauge.
does fuel log have a 1/8 pipe port in it? if so find a fuel pressure gauge at local auto parts store and hook it up. If not drill and tap fuel log for it and put in a gauge.
you may be over the psi that the needle and seats will safely take
And......mechanical pumps vary up and down (they may be rated at, say 7psi, but will run from 5 to 12), like suggested, put a regulator on it.TB
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