See pic – the first digit is not totally clear but it looks like 310. The gentleman who gave it to me said he couldn’t remember what motor it was on but I know he used to race both OMC and Mercury motors back in the 1950s and 60s. Maybe that narrows down the search.
![Michigan-Number](https://www.aomci.org/wp-content/uploads/2021/12/Michigan-Number-scaled.jpg)
Bob
1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20
“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."