Hirobo HI0404010 Starter Pulley Washer for OS Starter Systems  [HI0404010]

Starter pulley washer, OS fit

This Hirobo HI0404010 starter pulley washer is an RC-scale replacement component intended for use in pull-start assemblies that reference OS starter systems. It serves as a dedicated spacer/washer inside the starter pulley stack to maintain correct axial spacing and consistent engagement between pulley components.

The part is commonly listed among replacement items and common parts associated with Hirobo Eagle, Freya, EX and SX helicopter maintenance, and can be used where the pull-start assembly accepts the same washer form factor as OS starter systems. It is presented as a single replacement washer for repairs and routine service.

Installation is straightforward for hobby technicians familiar with pull-start disassembly: remove the starter housing, note the pulley and spacer order, replace the worn washer, and reassemble keeping original preload and alignment. No special tools beyond basic hobby drivers are required, though care should be taken to retain any small circlips or springs found in the assembly.

Tuning role: replacing a worn or flattened washer helps restore reliable starter engagement and reduces slippage or misalignment in the pull-start mechanism, supporting consistent starting behavior during bench maintenance and field checks.