Carb issues?

I have a 2006 Grizzly 660 and I think it has carb issues. Here is what has been going on with it……

When I got the bike, it either had full choke or no choke and would run fine. When you moved the choke to anywhere in the middle it usually would shut off. It also would do a quick sputter on take off and then run fine. The sputter would happen from time to time on take off as well. I had a friend take off the carb to clean it up, he said it had crap in it and he cleaned it out. He replaced a few gaskets and put it back together.

When I got the bike back, all those issues above were gone. After riding the bike for a while, the throttle hung up high (like around 2K/2500 rpm) on me while riding it. I had to ride it back to holding the brake to keep it it a good riding speed. I shut the bike off and let it sit for 20 minutes and a friend rode it for a while and said there was no issues with it. I then took it on a longer ride and had no issues with it at all. Later that same day I rode it again and the throttle hung up again. I hasn’t happened since then, but I haven’t rode it that long either.

Last night I started it and let idle for 30 minutes and then took it for a ride. I was at 20mph and then went full throttle. When I did that the bike fell on its face and the "R" light was flashing. I let off the throttle and tried it again and it did the same thing. I then eased into the throttle and got it to 30mph then went full throttle and had no issues at all. I turned around to go back home and tried it again. At 15 mph then went full throttle and it fell on its face and the red "R" light flashed again. I then went up to 20mph and went full throttle and it fell on its face and the red "R" was flashing, but this time I did not let off the throttle for like 30 seconds and it did not take off. At no point did it miss fire or stall at all

Any help here would be great.

The bike has 117 hours and 920 miles on it. Engine is all stock.