I have a 2011 Polaris sportsman 500ho. It started hesitating when giving gas. Was told was carburetor so ordered new one put it on still done the same thing and started flooding. Had the carb adjusted no more flooding but still hesitated on take off. Replaced the intake boot and it stopped and was running fine. Rode it about 5 miles still running fine. Then yesterday we decided to go for a ride. But his time there was 2 of us on it, before it was a single rider. No sooner than we get out the yard it starts hesitating, so returned to yard and one got off and went to go park it and it was no longer hesitating. But did notice it started flooding again. My question is why would it only hesitate and act up when there are 2 people on it and does just fine when single rider.

 

Did you replace the carb with the original Polaris carb or an Ebay/Amazon carb?
I would rebuild the original Polaris carb and adjust it properly.
Ebay/Amazon carbs are known to have problems and the original carb probably only needed cleaned/rebuilt.
One possibility is with two people your quad needs more fuel to get moving due to the extra weight and the new carb can not provide it. Just 1 possible cause.