Re: 1957 Johnson 10hp and 18hp gears Home › Forum › Ask A Member › 1957 Johnson 10hp and 18hp gears › Re: 1957 Johnson 10hp and 18hp gears XR55US Member - 2 YearsReplies: 310Topics: 30 July 9, 2018 at 10:59 pm #79291 They sold in sets, because you can not mix the straighter cut with the more curved gear teeth. The gear teeth would not mesh.