I have a BF75 that needs a little more oomph for our boat (C-Dory 22 Cruiser)like a BF90. From my study of part numbers and schematics the difference between the BF75 and BF90 is the carburetion. It may be the carb bodies or the jetting or something...
Has anybody else looked into this done this conversion? Similarly I bought a BF50 junker to restore and found that the carbs were the only difference between the BF40 and BF50..

I have the same question.I i find something i will let you know.Please do the same to me Thanks e-mail airbus1@hotmail.com