I recently purchased a T-bucket that has an Edelbrock AVS2 series carburetor. Last weekend I went out to start doing some work on it for the spring season. When I powered it on to start it, it would barely turn over. I put a battery booster on it, same thing. I pulled the air cleaner off and looked down the carb and it was pouring gas nonstop into my intake. I pulled the plugs to blow all the gas out of the cylinders. Do I need to rebuild the carburetor? If so, does it require a total rebuild or is there a particular place/thing to look at?

R.E.

The good news is that this is somewhat of a common issue with cars stored over the winter that is easy to fix. What usually happens is the fuel in the bowl evaporates, leaving the bowl empty. We’ll assume that you have an electric fuel pump based on your description. But this can happen with a mechanical fuel pump as well.

Since the fuel bowl is empty, the float is all the way down allowing a high volume of fuel to move very quickly through the fuel line. What often happens is a piece of dirt or debris will be dislodged when the fuel starts to flow through the empty fuel lines. This piece of dirt can get lodged in the needle and seat and hold the float down and allow the float bowl to overflow, creating the issue with fuel you noticed dripping into the intake manifold.

The cure can be as simple as removing the fuel line and inlet fitting from the carb and blowing air through the needle and seat and see if that fixes the issue. If this doesn’t solve the problem, then you will have to remove the lid from the carburetor to access the needle and seat assembly. Since you have the carb mostly apart anyway, it might not be a bad idea to buy an Edelbrock carburetor rebuild kit and replace the gaskets and both needle and seat assemblies (there are two). This decision will be based on the carburetor’s overall condition. If questionable, then get the kit and rebuild it.

If you’ve never had an AVS2 apart, there are several videos online that will show how to take it apart and replace all the necessary gaskets. It’s a pretty simple carburetor and very easy to work on. Be sure to remove both seat fittings as there are small inlet screens underneath the seat that may need attention. If there is a lot of junk in the float bowl or in the screens, you may have rust in the fuel tank that may need attention. If not remedied, this flooded carb situation will likely happen again.

An edelbrock AVS2 carburetor atop a muscle car engine
We’ve run the Edelbrock AVS2 carburetor on several of our mild daily driver style small-blocks with great results. They are really easy to do part-throttle tuning since the primary metering rods and power valve springs are easily accessible from the top of the carb without removing the lid.  (Image/Jeff Smith)

I really like the AVS2 because it uses primary annular discharge boosters that do a really good job of discharging fine droplets of fuel into the engine which allows the fuel to vaporize more easily and the engine will run much better with a leaner mixture.

Once you have the carburetor working properly, it is imperative that you also change the oil and filter immediately after the engine is running correctly. All that liquid fuel has drained past the rings and right into the crankcase diluting the oil. So the oil and filter must be changed, which is a good idea anyway since you are getting ready for a summer of fun with your car.

I’d also take the time to check the spark plugs and wires and determine if they are good enough. If not, install new plugs and wires and then hook up a manifold vacuum gauge and carefully reset the idle mixture screws. Make very small adjustments leaner and see if by doing so the engine idles at a higher manifold vacuum. Shoot for the highest vacuum reading, which will also require possibly slowing down the idle curb speed as well. This will also affect off-idle performance and the engine will probably feel a little better right off idle.

This little bit of effort shouldn’t require more than a few hours time spent on your hot rod that will return with a better running engine and more fun behind the wheel. Enjoy your new ride.

Parts List

  • Edelbrock AVS2 carburetor basic rebuild kit – EDL-1477
Keywords
AVS2, carburetion, Edelbrock
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Author: Jeff Smith

Jeff Smith has had a passion for cars since he began working at his grandfather's gas station at the age 10. After graduating from Iowa State University with a journalism degree in 1978, he combined his two passions: cars and writing. Smith began writing for Car Craft magazine in 1979 and became editor in 1984. In 1987, he assumed the role of editor for Hot Rod magazine before returning to his first love of writing technical stories. Since 2003, Jeff has held various positions at Car Craft (including editor), has written books on small block Chevy performance, and even cultivated an impressive collection of 1965 and 1966 Chevelles. Now he serves as a regular contributor to OnAllCylinders.