What's the part number or sizing for the o-ring used on Lycoming fuel pump fittings? I'm afraid digging it out will be akin to thesis research, so I'm hoping someone knows.
John,
According to my Lycoming Parts manual (O-320, 160 HP in this case), the O-ring is not a separate item. I don't think the Lycoming dealer will have a number.... so any part you get will be "unofficial"....
Use a MS-29512-6 o-ring. they can be purchased through Omaha Airplane Supply 800-228-9400. If they can't get them for you, I'll be happy to supply a pair.