Sounds like its time for some spring cleaning. could be running hot, fuel starvation, fouled plugs, old gas, gummed up carb or a combo of all of them... clean your carb Seafoam works if it is a small problem but yours sounds like I would go all the way through it. Change your water impeller, clean your plugs. and go fishing. If you dont know how, you will want to learn, after you pay the bill. I usualy save myself about $300 every time I open my tool box. the impeller is about $20, carb cleaner is about $6, seafoam is about $9 lots a luck ....PWW...