I'm sure its a 2 but is there a way to tell?

 

I am no expert, but they are quite different.. the most obvious differance is that a 2 stroke needs oil mixed in the gas (unless it has oil injection). Thats important to figure out, if it needs pre mixed fuel and you have just been running straight gas, the top end is probably shot already.

they also use reeds instead of a camshaft and I dont think they usually have oil in the crank case either, they use a dry sump setup

 

Then it's a 4 it runs straight gas.. for sure

 

check your timing because on my atv i had that kind of trouble and i change the gas and check everything like spark plug, carb ,electrical,everything so me i told my self i go check timing for the heak of it and there it was...it was timing after all ...so try that