i just bought a 74 bug 1.6 with a weber progressive 32/36 dfev and just rebuilt the carb. now when i start it, it idles really high. give it a little throttle and it idles really low. a little throttle again and it goes high. it will do that 3 or 4 times before it evens out. after that it runs great. float bowl is staying full. new fuel pump filter and in-tank strainer. ive adjusted the air control screw to every possible setting and checked for vacuum leaks at carb base, manifold and at the intake ports on the heads. Anybody run in to this before?