Here’s a link to my last build where Giorgio shared some more details about the one linked before.
I didn’t build mine exactly like that guide showed but it ended up turning out pretty good after some problems.
A bucket of charcoal like what you showed would run my generator for around 2 hours working it hard.
With the first simple fire charcoal gasifier I could be running the generator within a few minutes from lighting it with very little smoke. My last down draft gasifier has been taking a little bit longer to get good gas but almost always under 10 minutes and very little smoke. Of course, if you look at my build thread, making the charcoal could still fill the area with smoke depending on how it was made and if it was dry or not.
You have to be really close to getting your gasifier working. I think Dave’s idea could be why you can’t get it to light. Mine won’t stay ignited if the gas is being pushed or pulled too fast. Mostly I don’t worry about flaring mine. I light it using the mattress inflater and then hook the hose onto my generator. Most of the time when the gasoline in the float bowl is used up it is making good gas and all I have to do is get the air/fuel mixture adjusted and it’s making electricity using charcoal as the fuel.