I just was given a few old gas powered control line engines that I would like to get working. A few of them are seized up and I was wondering what I could soak the engines in to help free them up. Thanks, Chris

Chris, I've had good luck with a heat gun and penetrating oil. This will free them quick. Once they are free, flush the engine with fuel to remove the penetrating oil. Over time, penetrating oil will damage neoprene and silicone. A hair dryer will also work for a heat source. I've also read that putting the engine in a pan of boiling water will free it quick. The same flush with fuel would be required to remove the water afterwards. I plan on trying the boiling water method next time I'm faced with a gunk frozen engine.

Fill them up with marvel mystery oil, and work them slowly, they will free up well and be as good as they were. It works really well. Others have soaked them in fuel and done virtually the same thing.

I would disassemble the engine and use the crock pot method to clean it.
View my site for an article on how to do this.

Try the marvel mystery oil first. It works, and requires no disassembly. That stuff is magic.

I have dropped old engines in a coffee can full of Marvel Miracle oil and let them soak. They always have loosened up.