Standing in the boat, I removed the cover (had a rope inside cover for manual starting), I then removed the 6 inch band that surrounds the motor. I then took the top off the engine, noticing 4 plugs on the back. I could not find a serial number anywhere, however I found these numbers, P/N 332-5772A1, 73413, 50-66015, 1021 3514. I would have thought S/N followed by numbers. I think this engine is a 1973-1979. I need to get the motor tuned as when I try and troll, and or, trailer the boat, it always kills (maddening in current!). A dealership says they don't work on engines that old, even tried Twin City Motors, and they don't have anyone either. I did run across a guy who says he can do it out of his garage and that it would be about 45-60 minutes per carb. Any ideas or thoughts would be apprciated, thanks!