SBC Cold Start

[tntbower]

tntbowerSBC 400 with rebuilt and tuned quadrajet 850. how do I keep fuel to the carb so on cold starts it starts quicker?

 

[1987 GMC Jimmy]

How long is it taking? If the choke is working properly, and your fuel and spark are in check, it should be pretty quick. I'll usually do two pumps when it's cold, and it'll take 3-4 seconds. I suppose you could do a fuel check valve if you're running rubber lines, but the fuel shouldn't run away just sitting overnight.

 

[tntbower]

I'll check the choke. Thanks

 

[1987 GMC Jimmy]

You're welcome. Be sure to try and follow up if something doesn't look right to you.

 

[Altemose]

Even if the choke is wide open a couple of pumps and it should fire immediately and then stall. If the fuel is leaking down from the carburetor back to the tank it is either the fuel pump or it is pulling air in from somewhere. Generally we see it in the rust belt from dry rotten rubber lines that everyone is afraid to touch because the metal ones won’t survive. .


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[RustyPile]

Fuel can't get out of the carburetor via the fuel lines on a Q-jet.. If the carb is indeed, dry the next day after being driven, the fuel is probably leaking past the metering well plugs on the bottom of the carburetor main body.. Some rebuilders just stuff a gasket like "filler plug" in the cavity and call it good.. As a matter of procedure, I tap the plugs in a little tighter, then tap on the burnished area around the plugs.. As a final step, I cover the plugs with a small amount of gasoline proof epoxy..

A mechanical fuel pump has check valves built-in, no need for "auxiliary" check valves..