Zenoah had a G23 that came either way and it ran fine both ways. It obviously has an adapter in the spark plug hole. It will run fine as a Glow engine but may benefit from a larger carb as a glow engine. I have run my OPS 30 glow engine both ways and used a ZAMA carb from a Ryobi 31 when running it on gas, probably the same engine you're describing. W8YE on here can suggest a bigger carb if it does not already have one.