New vacuum petcock has prime, On, and Res. The on will only flow with vacuum from the engine, stops the carb from flowing gas into the oil in the case. Prime is free flow to pump. It is best to replace the vac line and the fuel filter. Vacuum line may be a different color.
 
Part # 44300-03G02
Fit Models;
      Suzuki LT-A 500 F Vinson Auto 4x4, (2004-2007
      Suzuki LT-F 500 F Vinson Manual 4x4, (2004-2007)