O.S. Engine Pump Unit Fixing Screw OS29067120 CSM3X18  [OS29067120]

Installation and thread care

This is an RC-scale pump unit fixing screw produced under the O.S. Engine part number OS29067120, identified by the CSM3X18 designation. It secures pump assemblies on O.S. Engine pump units and related RC engine pump components, functioning as a direct replacement or spare during maintenance.

Fit the screw with care to retain thread form and alignment: align the fastener squarely with the hole, make sure mating parts sit flush, and tighten in stages to prevent cross-threading. Avoid excessive force to prevent damage to pump housings or stripped threads, and inspect the fastener regularly for signs of wear.

From a tuning perspective, a properly seated fixing screw preserves pump geometry and seal compression, helping maintain consistent pump behavior. Keeping a spare on hand is a practical way to prevent session cancellations due to a lost or damaged fastener.