Modern Vespa

My 400 mile on the odometer 2024 Liberty 150 has stalled twice since my last gas fill-up (premium fuel always). I did overfill it accidentally so not sure if that is causing an issue. Both times it stalled was from a cold start - stalled after giving it some throttle. Restarted and ran fine once warmed up.

Any ideas what is going on? It is still under warranty but hopefully do not need to go down that path. I changed the oil at 300 miles, have not adjusted the valves yet (was going to wait for 600 miles).

Should add: engine oil light comes on when it stalls (goes away after restart).

Yeah, key on, engine off, oil light comes on. Not an issue. Light on when engine running is not good.

That overfill should clear itself if fuel got into evap system - but most likely just meant you had fuel in the rubber catch-up around the tank neck....drains to ground and causes no problem.
Your stalling when cold might clear with more miles.
If it stalls on the road while riding, see your dealer!
Mine used to idle down and die when cold many years ago. But restarted promptly and rode fine afterwards.
This cleared itself on its own in a few more rides.

Keep us posted on your experience!
O.S.
These things are pretty reliable!

So the issue seems to come and go. Today for the first time it stalled while still moving (was rolling to a stop). Very annoying. I'm still on the same tank of gas, so thinking it might be a bad tank of gas? Some days it is fine and other days it stalls….

Fuel pump.

Dodgy spark plug cap?

Goodness!
No fun thinking your scooter might die at a light in the middle of many lanes of traffic!
You can't ride this way.
Time to drop it off at the dealership - so they can experience this intermittent issue. Of course the risk is that they will try it 3 days - then tell you they found nothing wrong. Then, it will die as you roll off throttle up to your first red light on the ride home.
It seems like it is idling too low....then drops a touch more - which kills the engine.

Yeah - check the obvious things like a loose cap....loose spark plug....
Unless you bought your "premium" gas from a guy selling it in various colors in Coke bottles alongside a dirt road in a 3rd world country - "bad gas" is surely becoming little more than a wives' tale these days??! Wishful thinking.....just MHO.
O.S.