O.S. Engine OS27414020 Replacement O-Ring for S-36 75AX Crank Case Seal  [OS27414020]

Replacement O-Ring for Crankcase Cover

The O.S. Engine OS27414020 O-ring is a replacement cover plate gasket for S-36 and 75AX style model engine crankcases, intended to restore the sealed internal environment required for correct operation. It is used as a spare part during maintenance and repair.

Fitting is simple for experienced hobbyists: remove the cover plate, clean mating surfaces of oil and old gasket material, press the O-ring into the cover groove, then refit and tighten the plate using the manufacturer's torque values for case fasteners. Check the groove for any sharp edges or debris that might abrade the seal.

A healthy cover plate O-ring helps maintain compression and prevents air ingress that can upset running and throttle response. Replace the O-ring whenever the cover plate is removed, after extended service, or if the seal shows signs of deterioration.