Nylon insert lock nuts are great.

I would start by loctiting the parts on your carburetor that came loose on you allowing the engine speed to run away. Anything that shouldn't vibrate loose with time, and should sit still, can be loctited (as long as it is not plastic).

Don't get loctite on any carburetor linkages or swivel points (things that must move freely under normal operation). You don't want these things to get gummed up. That would be messy to fix.