Re: oil/fuel ratio 1964 evinrude 28 hp confusion
The bigger motors, from 10hp and above all were needle bearing motors. The older 10's had bushings on the wrist pin end but the rest of the engine was needle bearing set up. Later, the 10hp was changed to have needles running on the wrist pin, but I can't recall the year that was changed. As for all the old 15's, 18's, 25's, 28's, 30's, 35's and 40's, yes, they are all non-friction motors, meaning all needle bearing set up, since 1951.
1 quart per 6 gallon is a 24:1 mix, so I would go with what the decal in your motor specifies, but since you ran 50:1, we'll have to hang you upside down and flog you with a soggy carrot for three hours. Just kidding.
You should be okay though. The following year, they called out 50:1, but there was no design change in the motors from 64 - 65. This was just a new recemendation that the engineers at OMC came up with, after a weekend at the golf course. The smaller motors, 7.5 and smaller though, you want to stay with at least 24:1, but preferably 16:1, because they were all friction based motors, meaning, there were no needles at all. The 5.5hp was an exception, from 1961 and later. They converted to a needle bearing set up, so the mix went from 16:1 to 24:1 in 1961.
