Old incubator

[mlm Mike]

Thanks a lot guys! Gives me a starting point with how it works. Seems like even the patent is a lot different then how this one is built tho.. possibly a different model maybe

Good luck!

 

[Tabasco Jack]

I've got one very similar to yours that I have restored and converted to electric heat.
These have a water reservoir on the outside that you fill. Inside is some piping that the water flows through. A kerosene lamp or burner heats the water in the reservoir causing it to circulate through the pipes heating the interior. The thermostat controls the amount of flame on the lamp. There is no way to control humidity inside other than wetting a piece of burlap on the bottom tray. If your pipes and reservoir do not leak and the burner still functions, you could probably still use it that way. It would take a lot of trial and error to get familiar with it. Maybe, just maybe, Lehmans would have a copy of their manual you could get.
Here's the article and some photos of the one I've got: https://www.backyardchickens.com/articles/the-new-old-buckeye-incubator.72707/

I tried 2 25 watt heaters inside and it's not hot enough. I've bought a third one but haven't installed it yet.
Good luck with it.