GT33 Crank Shaft Prop Washer OS28309000 by O.S. Engine  [OS28309000]

Overview of the GT33 washer

This propeller washer fits between a prop and its retaining hardware on model engine crank shafts. As the GT33-layout part referenced OS28309000 from O.S. Engine, it delivers a reliable contact surface so the propeller seats evenly against the prop hub.

Installation requires only the same hand tools used for standard prop mounting. Slip the washer onto the crank shaft or adapter, add the propeller and secure the nut or retainer as instructed in your engine manual. Its role is to steady seating and cut down on positional differences when the mounting is tightened.

In bench tuning it helps achieve repeatable prop placement, which makes measuring minor balance or timing changes easier. It also serves well as a spare component for scheduled inspections and quick swaps during maintenance routines.