How to tell if hitting Rev limiter or just dirty carb?

My 660 sputters at mid rpm as if either diff lock limiter or reverse limiter is going but I held how the override button and didn’t help. Is that proper way to test? Getting my carb out is a pain. Idles like a champ but it seems if there is no load or not moving it doesn’t sputter. And I have my reverse switch grounded so I’m leaning towards carb but diff lock doesn’t work on my quad so I was thinking it could be that

Sent from my SAMSUNG-SM-G891A using Tapatalk