The Evinrude Lightfour is 15 cubic inches – 9.2 to 9.7 horse power. Johnson built the KD model. At 14+ cubic inches – 9.8 horse power. There KR model is built for racing with anti-fraction bearings. That model is hard to find & expensive if in good shape. The Mercury KG4H was a 15 Cubic inch class "A" racer. They were rated 7.5+ horse power. A good one would double that. A more modern "A" racer is based on the OMC 13.2 cubic inch 9.9 – 15 horse model. These modified models with there slim lower units run over 50 MPH. . . 😀
