Is it really possible to teach villagers to keep the fire stoked? I have tried and tried and still they never keep the home fires burning. Are they builders or what?
Because every time I leave my game I come back to an empty circle with a pot and a circle of stones.
Please help me figure out how to keep the fire burning.

I haven't been able to get them to do it either!

No, you have to keep the fire lit, the villagers don't do it. You can keep the fire going by just having someone collect more firewood before it goes out.

It does seem like a job the builders should do. Instead of inspecting and fixing huts that can never break (ever seen a hut fall apart? me neither), they should be setting fires.

Heck, even boy scouts and arsonists know how to start fires.

I would also like to know why people get sick when the fire goes out, yet when the fire is lit and they are at the other end of the island fishing, it can keep them healthy?

Just make sure you restoke the fire just before quitting. That will still give you 9 hours breathing space on 2x and a lot more on the other speeds.

The only reason I started this post was because I saw a post where someone said they taught thier villager to keep the fire lit. I have done everything to keep it lit. I just figured because there is help on other things like showing a person how to get builders more points when there wasn't anymore building left to do,that there might be a secret on how to keep it lit.
But evidently I misread the post.
Oh and by the way. why does the fire at times go as long as 39 and as low as 9?

The time changes when you change the game speed.