With out knowing what machine you have, may be a little difficult to diagnose.
Bad fuel filter
Leak in fuel lines, pulling air
Plugged fuel tank vent, vapor lock
Plugged fuel line, pinched or collapsed.
Bad or improperly adj. float.
Dirty air filter, air induction blocked(rats nest).
Bad spark plugs, plug wires, coil pack.
Bad Fuel pump.
Bad intake or head gasket.
The list is endless.
2012 550 Sportsman XP EPS Magnetic Metallic
Polaris 2500 winch
Polaris Glacier II+ 60" plow system
FallLine ware bar cutting edge
Polaris Front storage box
Guru front bumper
Wes AR 38 Box/Seat-modified (Lock and Ride)
Rear fender guards with foot pegs (ATV SuperStore)
Ricochet Armor Anodized (ATV SuperStore)
StarRider by Foreigner