1985 Bronco floods

1985 Bronco 4X4 with stock 400 cid 4bbl. Shortly after having leaking gas tank replaced by the dealer, my Bronco started flooding badly. It cold starts ok but after idling for 4 or 5 minutes it floods to the point of stalling. Then hard to re-start and once started I have to keep it revved up or it floods and stalls again. Black smoke etc. Autochoke is leaned as much as I can. Its not driveable. Might be just coincidence it started soon after gas tank replacement, or maybe flooding is related to pressure build-up or something wrong with the way the fuel and vapor lines are connected after gas tank repair. Or maybe disturbed dirt or rust from old gas tank, but it has a fuel filter. I procrastinate, dealer warranty is expired. I tried leaving the gas cap off - no difference. Any and all suggestions would be greatly appreciated as I'd really like to get it ready to use again in the bush in spring. Please help. Thanks.

Rod

You state auto choke is leaned as much as I can, but did you check to see if the choke butterfly is opened up when it is flooding? Just a thought.

Yep, its open. The butterfly never closes, with the spring cranked way over. Will not start that way in winter, but cold start in summer is ok with the butterfly open and it still floods bad enough to stall after 3 or 4 minutes.

SO it's carbed-did you adjust the jets underneath the carb? They could be open too much-especially if your autochoke is completely backed off. It takes some time to get the carb adjusted properly, and you'll find a big difference between the warm and cold starting stuff, but you already know that. Does the carb just need to be rebuilt? After 20 years, you might need to freshen up the pump valve, and the like.

If it started right after you got a new tank, the old one may have been clogged, and the carb may have been tuned to compensate. I'm sure you know where that leads.