I got a LT185 a few months ago and it ran great. I was riding it and it stalled so I started it and it pulled hard but started then ran a minute then stalled. Its now very hard to pull and stalls if it starts. Seems like there is something inside dragging it down but no smoke or bad noises. Any ideas?

 

The 185 started after a few pulls then slugged along and now makes a thumping sound every time the engine cycles. Bad crank bearing?