The 4 wheeler find good at times then other times it will only run half throttle wHen you get it over half throttle it will go to spitting and popping.

 

This can be anything from bad gas,a partially fouled plug can do the same thing,to an electrical problem. Simple way to rule out an electrical problem is to use a simple timing light. If at higher rpms when it cuts out,if the light flashes in time with the engine miss then it's more than likely electrical. If the light stays solid,no blinking,then the problem is elsewhere. I'd do the simple things first,new plug,check the air filter,check gas flow. Remove the fuel line from the carb and crank the engine over. Should be a steady steady of fuel. If not,could be a fuel pump or vacuum problem.Drain this fuel in a clear container to check for any water. Plus you can drain the fuel bowl to remove any possible trapped water or dirt.

 

I done the plug and the gas. It want take it long to act up.

 

Try the timing light and see. Plus the BEST trouble shooting checks are in the service manual. Wasn't much difference on the 2012/2013 models as they were beginning to phase the Fugi 500 engines out.2012 Polaris Sportsman 500 H.O. Service Manual PDF Download

 

What about the stator and the pulser coil

 

Yes,could be,and the stator resistance checks along with several other checks are in the cheap 5 buck manual.. That way you wont have to just throw parts at one..