My dad flew control line when he was young, and he told me they would just flick the prop and launch the plane. This was back in the 50's, so it has been a while, but he never had a problem starting any of his .049 angines.

Now the boat he built in the '70's which used a K&B outboard was a whole different story. It was the most finicky engine I have ever seen. It also ate connecting rods like they were candy.