Gator 6x4 sat for 2 years. New gas in tank (now), lines purged, Gas filter replaced. Looking for maintenance/adjustment regarding carburetor. Operates 'well', but only with choke 30-40% out, gas constantly dripping out of purge tube. What does the adjustment on the carb bowl do? There is a black plastic adjustment screw (needle valve?), but rotation is limited by metal tab, which seems to help. Can/should this be further rotated (requires bending metal tab up). Other than replacement, is there a rebuild kit available? Thanks.