Hello, I have a recently purchased 1987 9.9 Johnson. I am curious as to whether what I was told is correct. The difference between the 9.9 and 15 horse is strictly the rpm's. How true is this? If so, is there a way to raise the rpm's a bit to have more horsepower? Thanks!
Hello, I have a recently purchased 1987 9.9 Johnson. I am curious as to whether what I was told is correct. The difference between the 9.9 and 15 horse is strictly the rpm's. How true is this? If so, is there a way to raise the rpm's a bit to have more horsepower? Thanks!
