When the ski was winterized last year ran great.I removed the choke plates and installed a primer kit using the reserve line. @ 6-10 mph wot a bog , below 6 mph wot no bog I replaced the spark plugs and it fixed this problem. But driving at 3/4 to wot at high speeds it would randomly slow slightly and then speed back up around 50mph. So I figured I would clean the carbs which I usually do at the beginning of every year. Now at 2 mph wot rpm jump to 4000-5000 rpm then huge bog and shut off. Power valves are clean and servo motor working nothing sticking.if I give.partial throttle until 4500ish rpm and then wot no bog . Any input would be great . Thank you