69 340 problems

Sometimes we chase a fuel problem on an engine that could have an electrical problem.

My orange box was new. Ran good for a short while. Then started having problems as you described. Took the carb apart, (AFB at the time), replaced fuel pump, checked timing. Would not idle. Replaced orange box...problem solved.

You could still get a bad new electrical component.

The accelorator pump has nothing to do with the idle circuit on you AVS, although I never had any luck with those pumps.

I would bring No. 1 to TDC and see where your timing marks are. If its way off, (bad balancer or jumped tooth), resolve that first. Try to get you timing about 10* advanced for now.

If you have good flow from the fuel pump, it could be electrical or a plugged idle circuit in your carb.