I had thought the same thing. I have actually replaced the cap with a new cap. The more I work on this, the more I think it is fuel related. It acts like it vapor locks. When I try to restart it, it actually hits everynow and again. I took the carburetor apart and went through it. I found a little dirt in it. Cleaned everything and put it back together. It ran better, but still had the same problem. Any help would be greatly appreciated.

VR = Voltage Regulator. "Charging diodes" DO NOT "operate at about three amps", nor are they RATED at about three amps. They "operate" by design, within a range of current from zero amp.....to the maximum current that can be produced by the alternator of a specific application. If the maximum output of a given alternator was three amp, then the design would require that the rectifying diodes be rated for a minimum of "3 AMP". If the maximum current output of a given alternator was 25 AMP, the diodes would need to be rated for a minimum of "25 AMP" on so on ad infinatum. Now to the part about "bad battery will increase amps drawn possibly over the diode rating causing failure". Let us use an example scenario where the alternator can produce a maximum output of 25 AMP . If the battery was "bad" (let's say it has a "dead cell"), or just completely discharged (really makes no difference here), the voltage regulator would be operating to send the maximum design current to the battery in an attempt to raise the voltage level of the battery to the optimum design voltage for the type of battery used. At this point, the alternator is "maxed out" and the diodes are carrying 25 AMP (as they were chosen to do in this application). The fact that the battery is bad, or dead can only cause the alternator to produce the 25 AMP max output it was built to produce. High AMP Draw cannot cause an alternator to create more output than it was designed to.

Vapor lock will not occur WHILE an engine is running.Vapor lock occurs when an engine is shut down in a very hot condition and heat from the engine cause a portion of the gasoline in fuel line and fuel pump to vaporize. The heated vapor exerts more pressure than the fuel pump can deal with and so the pump can't work, until things cool off and the gasoline vapors return to liquid. You can test the fuel cap idea by removing the cap when the engine begins to falter. If it straightens out the running, the cap vent is the trouble. If not, then it may be ignition related.

If......gasoline is in the crankcase, it's not that a vacuum is created when the air filter is in place drawing out the gas/oil mix. Gasoline in the lube oil begins to vaporize out of the oil ( as soon as the piston and cylinder begin to warm, which is almost instantly upon start up) and creates its own specific pressure as it does so. This specific pressure will vent of its own volition without any partial vacuum being applied. What is actually happening is that when the air filter is installed, is that the venting gasoline vapors are confined inside the confined space created by the air filter and since the gases are coming out of the crankcase vent under pressure..........mostly what enters the carb is a fuel rich mixture with very little air because with a pressure fed source inside the air filter, there is no way for sufficient air to be drawn through the filter media to make a proper air/fuel ratio. Another phenomenon that may plague engine air filters during cold ambient air temps is air filter icing. In humid conditions with ambient air temps near or below the freezing point of water, ice can form on the filter media and cause drastic clogging. This is why most engine driven snow blowers/throwers do not feature an air filter. Both the fine mist of snow particles and the high water vapor content (from snow contacting engine and exhaust surfaces) produce conditions which are perfect for air filter icing.