This site show the different upgrade you can do to your predator 212 and other similar engines to get what they say is 26 hp. I did everything that didn't cost anything.
https://gokartsusa.com/Predator-212-Engine-Perfmance-Parts.aspx

Ill go through everything again and see what happens. Dirty carb is the only thing that makes sense but its weird how it runs for 30 seconds the shuts off like you turned the key.

I got about 13 hp out of a 6.5 hp 212 cc predator engine with less than 6 bucks. I strait piped it, removed the governor, made a custom air filter, and jetted the carb. The thing shot 6 inch flames out the exhaust then blew up putting a hole in the crankcase. Don’t rev it under no load and I’d say your fine. The engine was a couple years old and ran hard. Also their only $99 at harbor freight. Just remember, more air flow = more power. One thing to watch with the small engines at high rpm is if the pressure release on the cam gets stuck. If this happens it will be really hard to pull on the starting cord and you just have to open up the crankcase and tap it to get it to move.

We had a good gasket that we put in, but I haven’t checked if the needle is seating.