61ST-H O-ring Replacement Kit - YS Engine YSS7146  [YSS7146]

Service O-ring set for 61ST-H engines

This O-ring set from YS Engine is an RC spare part with model number YSS7146 and linked to the 61ST-H marking. It is intended to restore sealing surfaces on compatible 61ST-H engine assemblies used in radio-controlled models.

Fit this kit during routine servicing or full engine rebuilds when original O-rings are worn. Replacing aged seals reduces fuel and crankcase leaks and helps maintain correct crankcase pressure during running. Check your engine for the 61ST-H marking to confirm compatibility before purchase.

Installation is straightforward for modellers experienced with RC engine teardown; clean seating grooves thoroughly, apply a light film of lubricant to new O-rings to prevent twisting, and reassemble in stages with checks. This kit is intended for service and maintenance, not as a direct performance upgrade.