I have what seems to be an unstable O.S. 90 four-stroke without the pump. Seems the glow plug looses heat at certain times and stays hot others. I've wrecked to planes due to this problem. I'm using an O.S. F plug and it starts and runs fine, but very unreliable....could dead-stick anytime without warning. Therefore, I've decided to go with the setup shown below. Question is, how long will the two AA batteries last and can I go with higher mAh for longer flights? Actually, I've already got this installed in my H9 Twist using two Energizer batteries and it starts on them by just flipping the switch....which is kinda cool - eliminates battery box and twist on ignitors. Anyone else using this setup and if so how do you like it? Thanks.