The Stovebolt Site Forums The Shop Area Engine Shop Quadra jet or fuel pump??

Have a quadra jet on a 350 in my 50 model burb. It is very tempermental. manual choke, it idles fast, idles slow, dies at stop lights and exit ramps and recently has started to crap out upon shifting into third gear on any type of accerlation beyond moderate. Even died on me the other day upon hitting third gear and wouldn't start again until I primed the carb. Once I did that it ran fine and I made it the last mile to home.

Have had the burb about 6 weeks and the first thing we did was replace the wiring harness with a Haywire because the old one was melted together at the fuse box and it was a wonder it would even run.

So the conundrum for me is, concerning the crapping out and dieing, is it the carb or the fuel pump? This has been going on for a month. It's just one of those puzzles that I would like to figure out.

Just purchased an edelbrock 600 cfm off of ebay. Plan to overhaul it with a kit upon arrival. Plan to replace the fuel pump at the same time just to be safe.

Thanks,

Robert

Hy bbqhauler, fuel pumps "usually" fail outright, that is they don't supply fuel at all, rather than work sometimes and not others. Your problem sounds to me like a carb problem, more specifically a float level problem. I would do a fuel pump pressure check, and rebuild the "Q" jet, hope that helps.

Check the fuel supply to the pump first. What kind of tank does it have and whats it condition? Hows the fuel line look under the truck, any kinks?

I would start with the fuel pump if the rest check out, then rebuild the Q-jet. I am a firm believer in the Q-jet, you won't find a better all around carburetor. Keep the Edelbrock on E-bay where they belong!

Joe

Do a volume, pressure, and vacuum check on the fuel pump, in that order. Volume should be a minimum of 1 pint in 30 seconds at idle speed, pressure should be around 3 to 5 pounds, and stay there for at least a few seconds after turning the engine off. Vacuum should be 12 to 15 inches of mercury, and should also stay there for some time after shutdown.

The fuel inlet fitting on the Q-Jet has a pleated paper filter in it. Swap it out, even if it seems to be clean. It can be installed backwards, so make sure the open end of the filter with the 1-way check valve faces toward the fuel line when you install it. The spring in the filter housing should push the filter back toward the fuel line, also.

You've got the best possible carburetor for that engine already. Don't screw things up by swapping to a "will fit" aftermarket carb that's not designed to work with the engine.
Jerry

Nope - Good paper weight (if its clean), not so good carburetor.

As mentioned by others, check the fuel filter. Also check to make sure the tank vent is venting. You might be pulling a "vacuum lock" on the fuel tank.

With $3.50/gallon fuel, you will LOVE the Q-Jet when you figure out the issue.

Jon.

One thing Id like to mention is the phenolic floats tend to absorb fuel over time and with the extra weight, dont act correctly with the float height set properly. You can get brass replacements.

The Q-jets are awesome carbs, ONCE you figure out how they work!

Jeff