It sounds like the glow plug has burned out. Glow plugs can last for a few seconds or for years. They are like light bilbs. Sometimes they fail very early in their life. A new one is only a few dollars. You should always have a few spares anyway. Look closely at the element inside the glow plug. It should look like a spiral coil. It is unlikely that your igniter is bad. Charging it overnight should not hurt it.

If you're trying to start the engine without a 12V starter, save your money up and buy a 12 V battery and starter. Every serious glow flyer uses a starter at least some of the time.