This O-ring is a genuine OEM Yanmar part used across multiple applications on GM series marine diesel engines. It is primarily used for sealing the oil filler cap and is also used on the impeller pump of the 1GM10. This is a genuine Yanmar OEM product . Yanmar OEM Part Number 24321-000350 Compatible Yanmar Engines 1GM (7.5 HP) 1GM10 (9 HP) 2GM (15 HP) 2GM20 (18 HP) 2GM20 EU (18 HP) 2GM20 F (18 HP) 2GM20 F EU (18 HP) 3GM (22 HP) 3GM30 (27 HP) 3GM30 EU (27 HP) 3GM30 F (27 HP) 3GM30 F EU (27 HP) Questions about compatibility or Yanmar engine parts? Our marine specialists are happy to help.