Re: 1958 evinrude fastwin 18hp
Great motor. Love the 50s OMCs. I'd drain your lower unit and check for water. These old OMC lower units are usually long overdue for a re-seal of the lower unit. They have seals at the prop, where the drive shaft and shift shaft come down into the lower unit, and a spagetti seal around the two halves of the gear case. Any of them can and do leak. It's not too hard to reseal one and there are a lot of threads here to help you through it as well as lots of folks that know how and are happy to help. You want to see just gear oil when you drain the oil. If it's milky looking, that means you have water mixed in with the oil. Sometimes, you'll get clear water and oil. Either way, if there's water in there, you'll need to reseal the lower unit. Drain it by opening the two drain plugs on the lower unit that have straight flathead screwdriver slots. The bottom one is the drain and the top is the vent You remove both to drain it. DON'T remove the phillips screw the is near the bottom of the lower unit. It holds the pivot lever that shifts the clutchdog between forward and reverse.