hi everyone,

I have a pair of 1997 johnson 150 oceanrunners.Have had them for 5 years and had no problems.Serviced regularly.My starboard engine now after I run it at cruise for about 15 min. or so,around 3800-4000 rpm, will drop about 500 rpm very abruptly.It will then go back to cruise rpm.The rpm will then start jumping around eratically.+ - 500-800 rpm.I bring it back to idle and let it rest awhile, I can then bring it back up to cruise and it will operate fine for a bit then the whole thing starts again.Any ideas?? I am thinking ignition system....thanks in advance......