Hatroi HA237 Copper Gasket for #643 #644 YS4C-63~70 OS4C-70~81  [HA237]

Copper gasket for RC glow engines

This HA237 copper gasket by Hatroi is an RC-scale replacement sealing washer intended for use with the engine codes listed in the product name. It is offered as a straightforward spare part to restore sealing between mating engine surfaces during routine maintenance or rebuilds.

The gasket's role is purely mechanical: it helps fill micro‑gaps between the cylinder head and block to preserve compression and prevent external leakage common after disassembly or long running hours. Use the exact engine model codes shown in the product title to confirm fit before purchase.

Installation notes: ensure both mating faces are clean and free of old gasket material or debris, position the flat copper gasket evenly, then assemble the head and fasteners per your engine manufacturer's recommended procedures. Do not overtighten fasteners, inspect for leaks after a conservative run‑in, and recheck torque after the engine reaches operating temperature.

When tuning or troubleshooting loss of compression, replacing an aged or deformed copper gasket is a typical maintenance step that can clarify whether sealing rather than mechanical wear is the root cause.