could be clogging due to poor crankcase drainage of excess fuel oil mix. I would try 25/1 oil mix with quality oil open up or close idle mix knob a bit tocheck for reaction .
presumably carb has been gone over side channel flushed out top idle chamber cleaned out
measure coil resistance on secondaries (boot to grd should see solid 4-8kohms )
btw pump or pressure tank used ???
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