[Rugratman]

After the car sits for a few days, the carb and fuel lines are empty.
Everything from the pump up is new. Including a new quadrajet.
I have a clear fuel filter that is empty.
It has been suggested that it's today's fuel - issue.

RobbMc 550 pump. 3 years old.
Takes about 5 cranks at 5 seconds or so. Once it's primed and running, I am fine.
Check valve needed? Pump issue?

Thanks in advance


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[tjs72lemans]

I use to have that issue with ethanol fuel. I only use premium non ethanol now and I don't see that anymore. Try switching and see if it helps.

[steve25]

If any of the older hose in the system is dry rotted ( like back at the tank or jumpers in the front to the pump) or even if the hose clamps are not as tight as they need to be on the systems nipple connectors then the pump when driven will gladly suck air before is sucks much heavier fuel.
A old mostly clogged fuel sock in the tank will also make it hard for the best mechanical pump to suck in fuel .

Has this sock in your system ever been replaced?

[VCho455]

Mechanical pump on a carburetor engine 5 cranks at 5 seconds. I wouldn’t give it a second thought. My 91 S10 takes longer to start.

It's never going to start like a vehicle with electronic fuel injection and a in tank fuel pump especially after sitting several days.

[steve25]

If the carb holds it’s prime and the accelerator pump works, and the choke is set right then any of my motors always lighted up in 3 revolutions even in cold weather.

[Cliff R]

They don't make "new" Q-jets unless you bought one those Chines POS off Ebay.

Most likely the carb is assembled with the wrong parts. A windowed N/S assembly and POS pump seal will require considerable cranking after sitting a few days. The factory eliminated the windowed N/S assemblies in the mid-1970's the help prevent drain-back after shut down. These new "blue" accl pump seals swell up and don't allow fuel past to fill the well under them so poor pump shot for restarts. I've seen them so bad you get no pump shot at all. Every single time folks blame the problem on drain back or leaking bottom plugs in the carb and the problem is simply the pump seal too tight in the pump bore.......FWIW.....

[glenn911]

I had a Holley on my car and it would start with just one pump and NO choke anytime of year. I put a JET stage 2, Q jet on it and would have to crank/pump/crank/pump several times before it start. Then had the original Q jet rebuilt by cliff (runs great) but it still requires the crank/pump routine after sitting. I switched to corn free gas and it didn't change a thing.

[Bruce Meyer]

Originally Posted by Cliff R

They don't make "new" Q-jets unless you bought one those Chines POS off Ebay.

Most likely the carb is assembled with the wrong parts. A windowed N/S assembly and POS pump seal will require considerable cranking after sitting a few days. The factory eliminated the windowed N/S assemblies in the mid-1970's the help prevent drain-back after shut down. These new "blue" accl pump seals swell up and don't allow fuel past to fill the well under them so poor pump shot for restarts. I've seen them so bad you get no pump shot at all. Every single time folks blame the problem on drain back or leaking bottom plugs in the carb and the problem is simply the pump seal too tight in the pump bore.......FWIW.....

I had the same problem with a Q-jet and it had one of your kits in it. I know a LOT of people with Q-jets that have the same problem. With todays gas and the tiny thimble sized fuel bowl a Q-jet has, the fuel evaporates in about a day. I would have put a Holley on it but it was a #,s matching car. I sold it and the guy who bought it is pulling his hair out to fix it to no avail. My Holley equipped car can go a couple of weeks before the gas evaporates. I drive it every week and don't have to burn up starters to get it to start. One pump and it fires right up.

[Kenth]

Here is what the Delco/Rochester engineers said about evaporation, from the 1975- manual:

Also, the later solid, non-windowed, inlet seat was used for more consistant fuel flow, had NOTHING, to do with fuel "drain-back". The check valve in the fuel pump takes care of that.

FWIW

[Schurkey]

Originally Posted by Rugratman

After the car sits for a few days, the carb and fuel lines are empty.
Everything from the pump up is new. Including a new quadrajet.
I have a clear fuel filter that is empty.
It has been suggested that it's today's fuel - issue.

RobbMc 550 pump. 3 years old.
Takes about 5 cranks at 5 seconds or so. Once it's primed and running, I am fine.
Check valve needed? Pump issue?

TEST the fuel pump. Does it hold pressure when you apply ~5 psi to the outlet that would lead to the carb?

Does it hold vacuum when you apply vacuum to the inlet that would lead to the tank?

If the pump's internal check valves leak, you're going to have problems with fuel returning to the tank and the pump potentially losing prime, leading to long cranking times.

How hot is the carb mounting pad of the intake manifold? Stuck-closed heat riser (EFE) valve? One side of a dual-exhaust system restricted, including the inner tube of a double-wall exhaust tube collapsed with no visible external indication of restriction? Engine just plain runs too hot due to any one or combination of problems from lean fuel curve, retarded timing, insufficient water pump flow, radiator problems, etc.?

If the carb is overheated, the fuel is going to boil out at engine shut-down.

Originally Posted by VCho455

Mechanical pump on a carburetor engine 5 cranks at 5 seconds. I wouldn’t give it a second thought. My 91 S10 takes longer to start.

First Guess with no evidence:
Your fuel pump relay circuit has failed. Perhaps the relay itself, perhaps the wire harness, perhaps the ECM that drives it.

Engine has to crank long enough to build oil pressure, so the oil pressure bypass circuit will turn on the fuel pump.

Common problem. Easily diagnosed by the lack of 2-second fuel pump prime when the key is turned from "Off" to "Run".

Originally Posted by steve25

If the carb holds it’s prime and the accelerator pump works, and the choke is set right then any of my motors always lighted up in 3 revolutions even in cold weather.

But lack of carb holding fuel in the float bowl is the problem, isn't it. In this case, the guy claims the whole fuel system from carb down to the pump, including the filter, goes dry.

Originally Posted by glenn911

I had a Holley on my car and it would start with just one pump and NO choke anytime of year.

Holleys are often tuned to be pig-rich at idle. If you're in cold weather and DON'T need a choke for smooth operation of the engine during starting and warm-up...the idle is TOO DAMN RICH. You're washing the oil off the cylinder walls, leading to cylinder and ring wear, along with gasoline dilution of the oil leading to other problems.