The gearcases on most of the Pre1969 V4s of less than 100hp were a bit of an oddity. The props were actually smaller in Diameter than those used by the 25, 28, 30, 33, 35, and 40hp engines of the day. These engines had very little gear reduction in the gear case, 23:20. There were only 5 propellers offered by OMC for those engines.
10X12 large hub, long drive pin, and large prop nut
10X11 large hub, long drive pin, and large prop nut
10 1/4X10 large hub, long drive pin, and large prop nut
9 1/2X10 large hub, long drive pin, and large prop nut
10X9 1/4 small hub, short drive pin, and small prop nut
Michigan offered those sizes as replacement props and added
10X11 small hub, short drive pin, and small prop nut
On all of the large hub props the short drive pin and the small prop nut could be fitted and used
In later years, OMC only offered the 10X12, the 10X11, and the 10X9 1/4
We had the 10X11, 10X9 1/4 and 9 1/2X10. We used the 10X9 1/4 on our Evinrude Sweet 16 with a 1965 90hp about 98% of the time
Here is a prop chart for an 80hp(a slighty hopped 75) rpms and speeds would still match and the load rating a bit out (click on it, it
gets much bigger)
