Yes fix the firewall it sucks and dave will blame it on the gas engine knowing it is a defect and thats if you can contact him. My gas engine is im-fact lighter then the moki 1.8 he recomends after you put the added fuel the pump and what ever muffler you run. Mine made it 4 flights just glad it pulled the choke and killed the engine. He all most wouldn't talk about the fire wall after i sent a fax to him explaining i was having trouble contacting him and i had a defect. All he wanted to do was ***** me out for being unhappy with his support system. The firewall would have failed no matter what engine was on it there was very little glue holding it. Oh and if you are just getting started with aero-battics dont forget the cg needs to go forward a bit 6" is not so forgiving can you say snap with the quickness. later dudes good luck.