I just picked up an 86 Yamaha 25 for my Waco 14' jon boat. I can't find any info online for the 25's Yamaha made prior to 1988. It came with a new prop on it, but it's only a 10.5p. Assuming the max rpm, and gear ratio on the 86 is the same as the 88 (5500rpm and 2.08), I calculated a top...