My ‘96 Wave Venture 1100 runs fine up until about 1/3 throttle, then runs rough and bogs down. Also last time out noticed a LOT of smoke buildup inside the engine and battery compartments. Plugs are new, and gas I presume is good as I was regularly using Startron last season (didn’t put in fuel stabilizer during winterization however). Last time it ran without any issue was prior to last year‘s winterization. I‘ve only had it out twice this year, first time with old plugs, second with new plugs and Seafoam gas additive... Carb issue?