Check first your carburetor; then it's high risk that your injectors get clogged.
Learn more about the fuel injector cleaning method here:
If you don't know what is clogging, read this article:
If you're using regular 87 octane (cheapest gas), it's more than likely some fuel injectors, valves and intakes valves suffering from carbon build up.
Easy fix for that can be a darn good internal cleaning additive by Lucas or STP.
You might also find Youtube to be your best friend to see how using the cleaners works (it's not difficult at all).
Best of luck to you,