Did anyone ever find a fix for this? Mine is doing the same thing. Every gear including park and neutral. If you try to give it more than 1/4 throttle it pops,sputters and backfires. It acts like it would if you were in reverse trying to back up fast without using the override.

 

I've got the same problem..there's no way it's fuel related it's to consitent to be that it has to be electrical. NEED ANSWERS

 

There is a reverse rev limiter located on the little arm that makes contact with the clutch lever. When you put it in reverse you push the button which makes contact with the lever. If the lever does not return to its stop it will not let the motor rev. Reach under the clutch lever and find it and push it back to its stop. If the reverse cable sticks it will cause the problem. My raptor has the same set up and the same problem...good luck.