GY6 cold start issue

[scoot55]

Hello everyone.
Just a quick question I live in Florida lately it's been in 60s the during the day and in the 40s at night the problem I'm having with the my scooter is when you start it and it does start right up but the Idle is very erratic And if you give it too much throttle it'll stall out.

It does this until the scooter gets warm after I drive it about 3 miles or so it will then drive ok other than maybe an occasional stumble once in awhile when you try to accelerate.

I do notice when it's warmer like in the 70s it starts runs stops and drives just fine no issues.

I have two GY6 scooters the other one doesn't do this even in 45 degrees it starts fine and runs well.

I do let the scooter warm up before I drive off especially in the cooler mornings.

I am sure to let it Idle for about 2 minutes before I take off and when I do go I am sure to go slow and not accelerate quickly for the first mile or two to let it get warm.

I'm not sure why I'm having this problem the scooter that's giving me the issue is a 2016 GY6 Chinese scooter a QT 50 made by Hyosung.

It has 390 mi on it and was recently serviced it had a oil change and rear end fluid change as well as a good look over and was inspected and all looked good.

This issue That I'm having with the scooter started about 2 weeks after it was serviced I dont think its anything that the service tech did.

I think this is just because it's finally getting cold here and I am now noticing it.

As I said I have to GY6 scooters they sit right next to each other in the garage the other one has zero issues it runs, starts,idles and runs fine even in the cold weather.

that scooter has had its maintenance done at the same service Center. so I'm stumped


I'm hoping be able to shed some light as to why I'm having this problem.

The scooter does start right up usually on the first or second try but after I let it idle for about a minute and try to take off and give it just a little little gas that's when it stumbles hesitates and if I'm not careful it will stall out until it's fully warmed up.

I noticed even if I've gone several miles the idle will fluctuate up and down up and down if it's cold out like 55 degrees or so but if it's in the upper 60s or 70s it's fine.

any advice what to check?? I do use 93 octane fuel in both scooters.

[kz1000st]

At 396 miles it isn't broken in yet and probably is tight. Check for any loose vacuum lines or small cracks in the manifold. Start it and spray WD-40 around the carb and see if the engine sound changes. You might find a leak.