Larry, HS4s or HS2s? HS4s have self centering needles.
In reply to # 1595450 by Mgro1959 If is is SU carbs then the needle is probably not centered properly and piston hanging up. Undo the jet nut on bottom with the dashpot piston needle assembly in place raise piston up and down with middle finger a few times letting it seat. Tighten the jet nut with piston seated. This should center the needle and allow piston to seat and shut off fuel.
'S all for now