Both engines seem to idle and run fine and rev up to approx 3K without issue. Once I hit 3-3.5K engines will sputter and die if I don't back off. If I push throttle quickly past I can get engine to continue to run then operates great. Any ideas on this lag? In the motorcycle world I'd be suspicious of carb gum up and run fresh fuel with techron/seafoam etc to see if it will clear out. Ideas?