while flying yesterday my OS 46 FX. dead sticked. I brought it in and tried to restart it. It started but when I started to give throttle to take off it died. Did this twice. Today I tried to retune the engine thinking that was my problem, after about a hour and lots of curse words[:@] My dad said " try a new glow plug" with the old plug the engine will start and run fine till I pull the glow warmer. If the plane is at a slow idle it would die as soon as I pulled the plug. but I could idle up and it would run a while, then die. I put the new plug in it and the thing runs like new. Sure wish I would of thought of that an hour before all the madness took place. Is this normal for a glow plug that is going bad? Is this something I can expect the next time I have one that is going bad?