Re: 1962 Johnson 28hp
Many of the motors from the late fifties, sixties and early seventies share quite a few parts.
There was an evolution of motors that began in about 1956, and to a lesser degree even before then, that resulted in many similar models over about a twenty year period. The 30 and 35 hp models evolved into two different types of 35 hp motors - those with the "normal" midsection, and these with the "fat" midsection, which were commonly called "super quiet." The super quiet models had many differences, but a few things remained interchangeable. These motors also evolved into the fat midsection 40hp models that were so popular all through the sixties.
Where the most commonality of parts remained, was in the motors that did not have the fat midsection. In this case, the evolution was from a 25hp, to a 30hp, to a 35hp, to your 28hp model, to the later 33hp, and finally to a 40hp. I believe, however, that 40hp version has a larger displacement powerhead.
My point in bringing all of this up, is that there are parts for many of the other motors, that will fit yours. The earlier 25hp and 30hp models will have less commonality, but by the time you get to the '57 35hp, there are quite a few parts that are interchangeable.
One item that hits me right away is the electric starter. You should be able to use one off of any of these motors from about the '57 through the 40hp that you have been looking at. That said, the very old starters are two brush starters, rather than the four brush item that was used later on. You can the difference by the length of the starter, and by how many large screw heads you count on the side of the starter - two for a two brush, four for a four brush.
