I had an accelerator pump go bad on my original carb so I removed the top from the carb to replace it. When I reinstalled the top I noticed that the back butterfly flaps(in the carb lid) on the secondaries have no spring tension to keep them closed. I saw no type of spring before I removed the top and I dont think I lost anything as I was very careful about the top removal. What went wrong?

There is a spring, but it is very light. It may have broken, tho. If the butterlfy just literally "flops" when you flip the top over, then the spring is either broken, or the adjustment got moved. I'll see if I have something that will show the spring location...



Flip the top of the carb over, and look in the area shown in this pic. You'll see the set screw, and the small spring that holds the tension on the secondary flapper....check to see if the spring is broke, or if the set screw is loose, or something that would loosen the tension on the spring...Adams' Apple2008-01-01 16:29:09

Adam
Thanks for the response. There is some kind of screw under there that I can see. I guess I will have to remove the lid again to check this out. Another question would be with the secondary flap loose would it keep it from starting? I should say it starts but only runs for about a second and a half. Very rich exhaust and gas can be smelled. It may be flooded and need a plug change after trying to start it with the Accelerator pump bad. The rubber swelled and it wouldnt pump the first half of the stroke. In trying to start it I know it flooded as I was putting gas in the center breather for the primary feed. It would only pump once the pump had collapsed and moved down at that point. it is ok now but now it wont stay running with the flap like it is?

rod75152008-01-01 20:15:30

IF the air valve is sitting wide open, it will pick the secondary metering rods up out of the jets, and allow fuel thru to the engine. This could make is hard to start, but not likely, in my experience. It would, however, create a rich condition once running.
The purpose of the upper air valve is to enrichen the mixture when the secondary valves open. The vacuum created when the lower secondary valves pulls open the upper valve, which in turn raises the secondary metering rods, allowing more fuel to the engine thru the secondary throttle side of the carb.

Try holding the air valve closed, and see if the engine smooths out. It should. Then, you need to find hy the valve is "floppy". I can prolly get a couple of pics of the spring/adjustment this eve. when I get home.

Vette back up and running. I removed the top again today to find that the set screw muct have come loose. I set slight tension, then went 7/16th turn and tighten as the book called for. Works great. I may loosen that up just a slight little bit as I can tell a difference in the secondaries opening up. But it felt great to take for a quick drive today!

Hey Joel, that picture looks strangely familiar.  kstyer2008-01-05 21:15:29