Re: Mystery Johnson
My Johnson serial number list ends at 1962 with 2,249,094, Being that yours is only about 400,000 over that (about 2-3 years production in those days) I'd say your motor is right around 1965. In 1965 Johnson made an 18hp and in 1966 they made a 20hp - basically the same 22-cube motor with minor internal differences. You weren't likely to notice the difference in most applications... Your motor should have four small bolts and one large bolt holding the gearcase to the exhaust housing.<br /> 1964 was the first year of the low-profile 9.5 (only four bolts holding the gearcase to the exhaust housing), and I don't think anyone would confuse that with an 18hp, and the next size up in that era was the 28/33hp (six small bolts and one large bolt holding the gearcase to the exhaust housing) models in '64 and '65 - again - significantly larger and not easily confused with the 22-cuber.<br /> Hope that helps.<br />- Scott
