I installed a main jet adjuster last year works fine --now i'm on to the secondary --- i think i can use the boss that pushes up on the rubber plug -[ 1/4 x1/4 thk.] for an 8-32 x 1 1/4' s.s. Bolt -and remove most of the threads and taper to a needle ---i can thread the boss and use the rubber plug to seal the bowl -a tight hole in the rubber plug will help seal ---if i check my measurements right i will only need a 1/2 -3/4 turn for an adjustment -----wish me luck

 

Sounds like an interesting technical experiment. Pic would be real nice.

 

decided to go with a 6-32 ---had to make a tapered plug with a # 30 drill bit installed to line the jet center up with an over size hole in the boss ---after putting bowl on --I filled the oversize hole with pc-7 ---this will align the needle with the center of the jet ---I will try to get pic' posted

 

 

ready for solder fill to align the needle