I have a 2016 450 HO that will not start. Checked and replaced plug. Will start and run for about 10 seconds then die. Difficult to get it to start back up after that. If I do get it started and able to get to the throttle quick enough, It backfires. If it was carbureted, I would say choke sticking. I siphoned tank and added fresh fuel. No help. There is a high pitched whining sound when I first turn the key on (not talking about the EFI running at first). It is at the sensor that is plugged into the throttle body. I removed the air box so I could see inside the throttle body. The butterfly is closed. I can force it open a little bit with my finger but as soon as I turn the ignition on, it closes. My exhaust pipe next to the engine is turning blue. Again, in my head, thinking carburation, choke is closed. I'm at a lose right now. Hate to take it to the dealership and get raked over the coals. The machine is used around the land, no hard riding, no submerged riding. The day before it stopped running, I was running at a low speed spraying weeds.
Any ideas?

 

did you check what code it is throwing if any? that might head you in the bike direction. if the exhaust is bluing because of excess heat then it's running lean, not rich(choke would sticking closed). i'm assuming you checked to make sure the fuel pump is running and you checked the fuses.