Re: ANTIQUE OMC OUTBOARD IDENTIFICATION Home › Forum › Ask A Member › ANTIQUE OMC OUTBOARD IDENTIFICATION › Re: ANTIQUE OMC OUTBOARD IDENTIFICATION The Boat HouseReplies: 4550Topics: 111 April 25, 2018 at 2:05 pm #74733 With that battery ignition I believe your motor is a Model 401 Lightweight. The punch doesn’t look like it was square on tag when stamped.