Ralph check Carrprecision.com, wackerengines.com or ch-ignitions.com for prop hubs for weedie engines. Try matching up the shaft that protrudes out the flywheel, there's some basic sizes and a hub for a homelite or ryobi might just screw on. Echo makes good engines, the boat drivers use the 23cc size a lot and run them fast too, just watch your rpm's with a cast flywheel, they can fly apart. I'd say any engine worth converting for RC should have electronic ignition, you can adjust your spark advance way beyond the few degrees used on weedie flywheels, and get a lot easier starting, and if you go for broke and get electronic advance, you can hand prop it in a lazy fashion with no kickback. It's been my experience that you need a very fast flip on a hand start or a beefy electric starter to get a magneto engine going. Not to mention the weight of the flywheel and coil. You can usually drop about 12oz with electronic ignition. Ch-ignitions.com can supply it all. -Tom