A few weeks back we were out on the boat and I went to take off and the engine hesitated like one of the plugs were fouled up. Its been several years since I have had any plug issues so I didn't think to much of it so I went and replaced all 3 plugs. To my surprise that didn't fix the situation. It has actually getting worse. It starts on the first turn with no issues and idles good, but once you begin to give it gas then it would start "missing". It would usually catch and go after a few misses but now it just keeps missing. I don't know if "missing" is the right word but it feels like it was going to take off the stop then catch, then stop. My first thought is the spark plug wires/coils.I am thinking that maybe one of the boxes is arcing under load. I know the 3 wires have never been changed. I do get a spark from each box when starting with no load. If it's not that then the 2 boxes or even the stator. Has anyone had this issue? The motor has run great for so many years I figured someday something was going to come up sooner or later.