Fuel Pump Mech. GPH ? which one
#1
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Joined: May 2006
Posts: 172
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From: Centereach, NY
Motor is a sbc with vortec heads edelbrock airgap manifold and mild cam. with a quadrajet carb. I am going through some lean conditions above 400rpms was gph fuel pump should i be running is the stock 260 pump not enough? it was orignaly a nonvortec 350mag
#2
One big question:
Has this combination ever run properly in that boat?
If yes, then you are looking for something that has CHANGED recently. Plugged filter, kinked fuel line, failing fuel pump, plug wires, the list goes on.
If no, then you're looking for the above PLUS things like carb jet sizes and plug wire routing problems.
I doubt your stock pump is too small. It may be coming apart from the crappy alcohol in the fuel these days, but that is a failure problem, not a "too small" problem.
fuel requirements are pretty linear to the horsepower in a N/A moderate power situation.
<Ballpark>
200hp requires 17gph.
300hp requires 25gph.
400 hp requires 34 gph.
you can always put a tee in the fuel line near the carb and hook up a mechanical fuel pressure gauge. Have a buddy watch it as you run. It should remain constant.
Jetting can be checked with a plug chop.
MC
Has this combination ever run properly in that boat?
If yes, then you are looking for something that has CHANGED recently. Plugged filter, kinked fuel line, failing fuel pump, plug wires, the list goes on.
If no, then you're looking for the above PLUS things like carb jet sizes and plug wire routing problems.
I doubt your stock pump is too small. It may be coming apart from the crappy alcohol in the fuel these days, but that is a failure problem, not a "too small" problem.
fuel requirements are pretty linear to the horsepower in a N/A moderate power situation.
<Ballpark>
200hp requires 17gph.
300hp requires 25gph.
400 hp requires 34 gph.
you can always put a tee in the fuel line near the carb and hook up a mechanical fuel pressure gauge. Have a buddy watch it as you run. It should remain constant.
Jetting can be checked with a plug chop.
MC




