I have a 2013 850 stealth black it cranks and runs fine for a while then it will start spitting sputtering back firing and dies. Let it set a few minutes then it will crank and run a little then all over again. I checked the timing gear on crank shaft for spun gear and it is in place. It has 115 hours and 650 miles. Installed new plugs but still same issue. Any ideas or help???