While making a run on my local lake I had a sudden loss of about 5-7 mph at WOT. It lasted about 5 seconds an then went back to normal MPH. This happened several times on that run and then stayed at the lower MPH until I shut her down and went home. I changed the spark plugs and went out the next day with no issues but the day after that I had the loss about 3 miles in my run and it never came back to normal MPH. At Idle it sounds different. Kinda "muffled" but idling fine not missing or idling rough. I don't want to do any damage but the water is calling my name. Thoughts?
David