(37) Tillotson HW-33A Throttle Shutter (Butterfly)

(37) Tillotson HW-33A Throttle Shutter (Butterfly)The Tillotson HW 33A throttle shutter is the butterfly valve disc that controls airflow through the carburetor bore. The shutter rotates on the throttle shaft fully closed at idle, fully open at wide open throttle. The shutter's edge seal and fit determine idle quality and off idle transition responsiveness. Replace if the shutter shows wear marks on the edges, is bent, or no longer seats squarely in the bore. A worn shutter allows air to bypass at

Replace the pump body if the internal surfaces are scored

251719 or R

The Tillotson HW-33A inlet control lever is the fulcrum arm that actuates the inlet needle in response to metering diaphragm movement

Includes: Complete mounting hardware kit

Quantity: 1 drum (sprocket and roller cage sold separately)

A damaged or dented header alters exhaust pulse timing and costs power

Quantity: 1 packing

which matters for handling balance

Style: Split two-piece

allowing the sprocket to rotate freely until clutch engagement

or any racer competing in high-grip conditions where controlled chassis flex translates to faster lap times

Chain Type: #219