Re: johnson 5 1/2 hp
Welcome Terry. The 5? was produced from, 1954 through 1964; as such it should run a 24:1 gas / oil mix with modern lubricants. Although they are basically the same, there were some updates to the design. The original lower unit was used 1954/55. It was revised in the midsection where the lower swivel bracket mounts for 1956 and ran through the end of production. It even carried forward on the 1965 ? 1979 6 horse.
Does your motor have a hinged metal cowl with fins, or does it have a fiberglass removable cowl? 1959 was the year they switched to the fiberglass cowl. The 5? was green in 1954/55, bronze in 1956-58, then white 1959 ? through. That is relevant of your motor has never been painted of course. 1954-59 used the dual fuel lines with the pressure tank; 1960-on used a single line with a non-pressurized fuel tank (with gauge) and a fuel pump.
I don?t think that the average person can tell the year of the motor by the serial number, but a dealer could. Is there a metal plate on the transom bracket? If so it will have the model number. Assuming it hasn?t been put together out of several motors, the serial # on that plate should match the number on the metal plug on the block.
Browse this site:
old-omc for the various Johnson brochures and you should be able to tell the year of your motor.
