Boyesen APC-3QS Quick Start Tunable leak jet maximizes volume of fuel and duration of squirt for all conditions Integrated hot start assist eliminates problematic 4-stroke hot start procedure High volume vertical check valve located in the QS3 for precise, consistent fuel metering Patented design stops bogging, improves throttle response and low end performance Older models with carburetor mounted hot start knobs and electric start models will require a separate O.E.M. or aftermarket handlebar mounted hot start lever