need help!!!!!!

Hi I’ve been reading the forums on here since the day I bought my 2013 grizzly 700 and it has helped me out a lot instead of going to the dealer so I hope it works for me again well my friend put 50:1 mixed gas in my quad so I’ve been just trying to burn it threw well can’t do that anymore hahaha anything over 1/4 throttle the motor is back firing stalling I can ease on the throttle and it will build the rpms up it idles fine but the second you goto just punch the gas it coughs back fires and dies it almost sounds like way to much air but I don’t have a clue I could only go 25mph anything over that speed it would fall on its face and almost stall out I am going to drain all the gas out do an oil change filters and put a new spark plug in cause its pretty black but the very tip you can tell it’s running hot by looking at the plug I’m pretty sure I fouled the plug but the dealer said it could be the throttle sensor assy and that’s 130 plus tax plus another 90 for them to look at it so any help would be greatly appreciated cause I want to change everything and run some sea form threw it and hope it works this quad is my baby its the first thing I ever bought new please help it’s a 2013 efi se eps PLEASE HELP thank you

need help!!!!!!

Hi I’ve been reading the forums on here since the day I bought my 2013 grizzly 700 and it has helped me out a lot instead of going to the dealer so I hope it works for me again well my friend put 50:1 mixed gas in my quad so I’ve been just trying to burn it threw well can’t do that anymore hahaha anything over 1/4 throttle the motor is back firing stalling I can ease on the throttle and it will build the rpms up it idles fine but the second you goto just punch the gas it coughs back fires and dies it almost sounds like way to much air but I don’t have a clue I could only go 25mph anything over that speed it would fall on its face and almost stall out I am going to drain all the gas out do an oil change filters and put a new spark plug in cause its pretty black but the very tip you can tell it’s running hot by looking at the plug I’m pretty sure I fouled the plug but the dealer said it could be the throttle sensor assy and that’s 130 plus tax plus another 90 for them to look at it so any help would be greatly appreciated cause I want to change everything and run some sea form threw it and hope it works this quad is my baby its the first thing I ever bought new please help it’s a 2013 efi se eps PLEASE HELP thank you