I've got an 06 12F with 41 hours that this year has started running rough in the mid range. It feels great at full throttle (runs 54 mph with me at 250 lbs, the same as when new. But if you run it at mid range, it feels like it runs rough. And sometimes after extended midrange (one or two minutes) it doesn't want to rev up to full throttle. We changed plugs yesterday with no effect. Any ideas of what to check next?
Thanks,
Jeff