I am rebuilding a carb that appears to have some warpage to the main body, centered on the underside near the main well plugs. On startup after the rebuild it was idleing and adjusting fine until I opened the secondaries with a WOT stab. It developed a large vacuum leak at that time, and adjustments went to H*ll. All the symptoms of a vacuum leak. The next time I opened the secondaries it backfired up thru the carb and quit. I have attached pics with a steel rule from the front and rear, as well as a pic of the "incomplete" impression left in the main body gasket. The gasket has some indications of the backfire between the primary and secondary bores. The baseplate checks flat and straight. This is a 1973 carb. I note that the main body has the third (center)baseplate screw location already tapped. However the baseplate does not have the third hole for a screw like the earlier models (68,69 ish). So I am looking for solutions, and advise from those who have experienced or dealt with this problem. Some Ideas: 1) a flat file 2) a Qjet unwarping tool 3) drill the baseplate for the third baseplate screw Thanks for your thoughts....
That small amount of warpage is not the issue. The gasket is thick enough to effectively seal the parts up with a lot more warpage than what I'm seeing in the pic. Take a closer look at the secondary throttle plates in the baseplate. Gently loosen the screws and index/center the plates to be fully closed. While holding light pressure on them, re-tighten the screws, then test to make sure they are fully seated and even on both sides. Open them up several times and make sure they return to the fully seated position each time. We sell new secondary shaft springs if you find the stock one is "weak"....Cliff
