Now I have a lot of experience with carbs and such, so I'm thinking its not an adjustment issue. What are ya gonna adjust?
It more than likely is the anti-afterfire solenoid ( fuel solenoid) that is probably sticking open, or not seating , due to crud, etc.
Pull the solenoid and check it out.
You also wanna pull the shroud and make sure the head/cyl fins are clear of debris.
" But let me tell you something ,folks: You can't fix stupid!
There's not a pill you can take, there's not a class you can go to. Stupid is forever!"