You have one of those testers (the new one that that does spark 400-18000 rpm and hall sensor), and used it to run the ignition? You got spark out of it. Then it is good.

Soo..... unless the air pressure there has gone to 0, you have a fuel problem. I just reread post 107.You do not have consistent fuel. you have air and spark.

Air, fuel and spark, keep it simple. everything else you are looking at should be run, but, run badly..

Rebuild or clean the carb , check the pump and pressure pulse, the regulator and needle seat. The needle settings high and low. flow through the passages.

this is my 2 cents.