nice to join. My zenith 36iv on my series 3 started giving trouble recently,drinking gas and shutting off.bought carb #1 clone zenith no specs and claim to be bearmac by seller,no good idles heavy and backfires.Carb#2 webber34ICT,no economy diphram and choke linkage and made in italy,no good idles heavy and holds back when pulling off.The mechanic had brought a used working webber34ICH with economy diphram and choke linkage worked well idles and pulls off smoothe.After About 3days it was cutting off when mashing brakes and smelling mild gas fumes while driving,there is'nt any valve on the brake booster line.P.S. are there imitation webbers out there?He decided to service the zenith 36iv with full carb kit and rebushed the shaft,he had put grey silicone on 2 sides of the o-ring,he said it was sucking air and when tried it on it was smoking very black and smelling gas via the exhaust.I've decided to seek second opion.Just in case i may need a new carb i sourced one from famous 4,are they reputable? These auto shops only have imitation carbs,new tune up parts and mild engine job were done to my series,bent intake valve.Appreciate your response

Wow can you repost that using some paragraph breaks?

From what I can tell you are having some trouble with a Zenith carb. These are prone to warping and the two havles of the carb body move apart causing excess air to be drawen in.

If you Google for "Zenith carb warp" then I'm sure you will find plenty of information.