I glanced at your previous thread, I would have used the Brigg's specs for the valves, they are the ones who actually made the engine after all. As for the gas in the cylinder, it sounds like your needle valve in your carburetor is not sealing. Be careful with this as the fuel can potentially leak into the crankcase and thin out your oil. Pull the dipstick and use a lighter to try to ignite it. If it catches, you have gas in your oil, a basic pocket lighter will not ignite motor oil.
As for the electrical issue, the engine should have a stator underneath the flywheel that produces a small charge to keep the battery fully charged (as well as powering headlights if your unit is so equipped). This may be faulty, or you may have a wiring issue somewhere that is preventing the stator from charging the battery.