150cc Brand new, starting/idling issues

[Gene563]

It's the tiny orifices that are going to mess you up. I haven't had this problem yet, Luckily. If you pull the carb, I would start by cleaning out the mixture screw housing with carb cleaner, remove the jets and do the same; also, the enricher housing has small ports that (I believe) run to the carb throat. Try spraying them, let them sit for a while, and spray again.

I thought I had a similar problem; I left gas in the snowblower. It started, but ran like crap. I cleaned the main jet and whatnot, but it turned out to be a vacuum leak. All good now.

Good luck.