An experimental rig might be setup as thus:
Put petrol (or any liquid hydrocarbon fuel) into a bottle, or a solid container with an opening at the top. (A wine bottle or whisky bottle seems ideal)
Attach a solid tube to the top of the bottle, set up in such a way that allows only vapour to escape, not liquid.
Disconnect liquid fuel line to carburettor.
Attach the outlet hose to the manifold of a 4 stroke engine.
Start engine, which will apply manifold vacuum to the bottle, and lower the boiling temperature of the fuel.
Possibly use some hot water or exhaust heat to aid the boiling process.
When the bottle is empty, you could possibly burn any residue off it with a blow torch, or discard the bottle.
I think the GEET fuel system and a few others work on this principle, except they include some cock&bull regarding installing a catalytic rod of a tuned length, which is tuned by pointing it north for 45 minutes and applying quantum orgone plasma to it.
