Stock 2006 450 Rhino

Engine starts up and idles good but at WOT it hesitates every few seconds.
Has sat for over 6 months, changed the plug, fuel filter, air filter, cleaned the fuel pump and carb.  Less than 2 hours on engine since Yamaha shop did complete service.  Put in new CDI box still runs the same.  Am I missing something?  

Buddie

Sounds fuel related to me. Cracked fuel line???

If your fuel pick up and lines are OK them an electric fuel pump may be the answer.

If the 450 sat for 6 month there is a good chance the fuel is old in the tank. The second thought is if you're running WOT you're more than likely bouncing off the rev limiter. Put a dyna-tech CDI on the 450 and eliminate the rev limit problem, plus pick up some more top-end on your Rhino. Get with JBS and he'll fix you up with the CDI if you go that direction. Drain the old fuel put some 90+ octane fuel in there run it and see if that solves the problem, but if you're holding it WOT and it hits the rev limiter it's going to have a dead spot until the revs die down them rev back up and do it all over again.......... Got a 450 myself know how they respond.

Never thought about old fuel, that makes a lot of sense. Regular fuel lasts about 3 months, High test lasts about 6 months.

Thanks everyone now I know what to do.  The new CDI is from James and I also got his sheave. It now goes 4mph faster with more power. 

Buddie