Could be a lot of things. fuel pump, fuel filter, blockage in the fuel line. These models quite often have trash that collects in the fitting right under the fuel tank. Loosen the fuel line on the suction side. Fuel should gravity flow out of the tank. Another thing that can cause this is a bad coil. When the coil heats up, the windings expand and short out. If you eliminate fuel, try a different coil and check other things like an intermittant ignition switch or a primary wire that is rubbed and grounding.
