Some of you gents that have flown yours may be able to give me some advise. I have an O.S. 300 twin four stroke or a Moki 1.8 that is available to go in my GP PW Extra. I am not prepared to buy another motor at the moment, although I would love to drop in a 50cc gasser, it is not an option. Cobra, are you concerned about fuel consumption with your O.S. 300? Did you add an extra tank for more capacity?