Step 2: The carburetor
One, if you screw it up and it doesnt work, then you still have your original one to put back on your engine.
Two, if you decide to later return your engine to operate off gasoline, it only takes a min or two to put the old carb back on.
Three, you will have a way to run your engine on two different types of fuels. Could be useful in a crisis when gasoline might become scarce.
You can obtain old carbs possibly by visiting a local small engine repair shop. They might give you one cheap if it cant be used on a gasoline motor anymore. Another source is to look for the same type of carb or engine that has a carb, on an old mower or some other engine that doesnt run anymore. Look on craigs list, garage sales, ebay, neighbors backyards, trash dumps etc etc... any carb that will physically fit your engine should work for this even if it is gummed up from gasoline. Possibly if its from another mfg, just as long as the mounting flange and openings are the same.