I have a 1993 Johnson 115 Model TJ115TLETS that I bought new and has few hours on it. I started experiencing a problem where it would run OK for a while then lose power when I went to throttle up. Starts and idles good. Used Clymer manual and checked fuel system, stator, pwr pk, coils, spark @1/2" all seem good. Noticed "clean" plug in #4 and evidence of water in cylinder. Any suggestions on what to look for and how easy is this to fix?