What does the top control knob do? This is a Binks M1-g spray gun. The bottom knob controls fluid but the top knob doesn't seem to make a difference on anything. I
Binks Model 2100 Spray Gun, Conventional, 68SS-68PB-P Nozzle | Spray Equipment & Service Center
BINKS MODEL 95 GRAVITY SPRAYGUN | spraygunparts.ca