OK I just bought this boat and it has a 1999 Yamaha 200hp VMax on it. It came with 2 props....a ski prop and a power prop. Anyway, with the ski prop on the castle nut tightens down far enough to slip the cotter pin in. But with the power prop on I'm not able to take the castle nut down far enough to put the cotter pin in. What am I missing?