Re: 1957 Johnson 35 hp Mercury switch Home › Forum › Ask A Member › 1957 Johnson 35 hp Mercury switch › Re: 1957 Johnson 35 hp Mercury switch jw-in-dixieReplies: 371Topics: 23 January 13, 2018 at 8:38 pm #69638 BTW, I suppose mercury switches are hard to find. Search for old thermostats and rob.