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

Copper sealing washer 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 minor gaps between the cylinder head and block to preserve compression and reduce external leakage that can occur after disassembly or extended running. Use the exact engine model codes shown in the product title to confirm fit before ordering.

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 following your engine manufacturer's recommended procedure. Avoid overtightening fasteners, check for leaks after a cautious run-in, and recheck torque once the engine has reached operating temperature.

When diagnosing loss of compression, fitting a renewed or correctly formed copper gasket is a common maintenance step that helps determine whether sealing or other mechanical wear is the underlying cause.