The Stovebolt Site Forums The Shop Area Engine Shop Have to always prime carb, why?

I have a particular Quadrajet that no matter which truck I put it on, I have to prime it by pouring gas into it to get it to start. It then runs fine, and will start again if I restart it within a few hours. I can get it to start by copious pedal pumping and cranking, but it is difficult. I just rebuilt it, and it performs great, but in the morning, I am best off popping the hood, pouring in some gas, then cranking. Is there a solution?

First, does the accelerator pump squirt fuel into the throttle body when you pump the gas? If not, you probably have either a bad pump or the piston installed wrong. If it does squirt fuel, check the compression on your engine. I would guess leaking rings and valves, needing excess fuel to get started. I worked for a lumber yard with a fleet of worn out GMC 351's, we had a squirt oil can filled with gas every morning.

YOU NEED A FUEL FILTER WITH A CHECK VALVE IN IT

Q-jets have a little soft metal plug underneath the bowl that can leak down into the intake manifold and you will never know it except the bowl will drain itself dry pretty quickly with no explaination. It drains into the intake so you never see or smell the gas. You have to take the bowl off the throttle body to see it. I bet that is leaking, causing you to have to crank the fuel pump until the bowl fills up so you can start it. It covers one of the drilled passages to the main jets. You need to cover it with JB-Weld or your favourite epoxy and I bet that will fix it. I ran into the fix in a Rochester carb book (can't remember which)
I have rebuilt 2 Qjets, one in my Jeep (off a 350 Buick) and one in my dad's boat (350 Chevy). The one on the jeep leaked.

hello tp sierra. like was said, if the carb leaks down on you , you'll get these symptoms, but you didn;t mention the opperation of your choke. if the choke isn't closing on initial start-up with a cold engine, the problem will be similar. you can check it by opening the throttle before you start the cold engine to see if the choke is closing. if it is not the engine will start real hard and need copius amounts of throttle pumping to get it to start, especially in a cool climate. good luck.

It was the knarly epoxied plugs at the bottom of the bowl. I wonder why the rebuild kits say nothing about this.