Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

It does seem there are varying schemes. I once knew a fellow who drove a Model A Ford truck converted to propane. He cobbled together a demand regulator that was operated by manifold vacuum to admit propane straight into the carb throat. The truck ran well, driven almost daily in the snow free months as late as the mid or late 80s.

I’ve seen the video linked above. The hot bulb engine and essentially a stove type mixer to push propane into the inlet. I think the stove type mixer might be fine for constant speed, constant load applications.  The propane would be controlled just as a stove burner or propane torch is.

The demand regulator used on conversions of carburetor engines seems the better route for varying speed and load as one might have with a leaf blower or generator. Just pondering.  I have a small hobby type propane torch. It’s the kind with a hose from the bottle top valve to a pencil style torch with the air mixer.  A bit of brass tube from the torch head to the mixer inlet on a hit and miss wouldn’t be difficult to cobble together. In theory one could even cobble up a hybrid that started on petrol, before opening the gas valve and closing the petrol needle at the mixer.
Alternatively the petrol needle might be useable as an oil injector if running on propane.