If it was red locktite, then drilling it out will probably be your only option.

If it was blue locktite then follow piper_chucks advice and grind a slot in the head of the bolt, then use a soldering iron and heat the bolt down at the threaded end, this will take a little time but get it as hot as you can, this will release the locktite so you can turn it out. I use the heat trick to get out servo screws on metal gear servos to replace the servo arms, works like a champ.

The other thing, since this is on an engine, if you have one of those little butane torches Hobbico makes you can use that to heat up the bolt, just be careful and apply the heat slowly and evenly. Even a propane torch on low heat would work.