M38A1 fuel tank cleaning?

[Casey B]

Hi Rob yes I found the POr15 coating now wanted to know how you would protect the drain hole just let it run through and then run a tap through the threads after or put a bolt through then try to cut away the residue or build up after it is dry?

Also I was told the running for a few minutes then dying could be the condensor you think maybe? New plugs proper gap and clean fuel rebuilt carb...Idled for a long time 15-20 mins and then when you put it under load it dies within a few minutes and is flooding and will not restart!