GY6 keeps dying

[regdude]

Hi!
I have a Chinese 50cc scooter with a GY6 motor, I think it is called Benzhou YingYing (2006).

So I have it since 2006 and last summer some problems started to come up.
Last summer it started to die randomly. I had to wait about 10 minutes for engine to warm up in order to be able to drive it, otherwise when I gave some gas, it just lost RPMs and died. But it did that also when I was trying to warm up the engine, RPMs are too unstable. In order to drive it, I had to keep RPMs high, then I could drive it, but if it died, then I needed to wait about 2 minutes and only then I could start it up again, otherwise it simply did not start up again. I found that the carb was leaking gas by the booster (I don't know how it is called, but it's a some kind of a diaphragm that pushes extra fuel when full throttle is given), so I used silicon glue to stop it from leaking. When the summer ended, I took off the carb and took it home.

Now I tried to start it up for few days and it is almost impossible. I need to keep it starting up for about 10 minutes and then it shows some possible signs of life, but it keeps dying (still RPMs too unstable). When the engine has warmed up, then I can somehow drive it (keeping RPMs high), but that is the least problem.
The largest problem is that it keeps dying when driving. No matter how fast I drive it, but after 2-3 minutes it starts to loose speed and eventually dies, then I have to wait about a minutes and then I can try to start it up again.
And this cycle goes on forever.
I tried adjusting the air/fuel mix screw many ways, also the idle screw, but no results, those 2 screws only help to start it up for the first time.

I haven't changed the oil since 2008 and the engine oil is clear, it really needs to be changed.
What could be the problem?
I don't think is it the oil, but maybe the electric choke?

[inuyasha]

Hi
Welcome aboard
Pleased to meet you
Have you ever checked and adjusted the valves?
Hard starting rough idles and stalling are all symptoms of improperly adjusted valves
I would check them first
Take care and ride safely
Yours Hank

[regdude]

Well I have.
I also tried to do it after the GY6 guide, where you adjust the idle speed to high and air/fuel mix screw turn 1,5 turns C-clockwise when the screw is in, but no luck with that too.

It is impossible for me to get a stable motor, it always dies no matter how I adjust those 2 screws. I always get too unstable RPMs or the back tire spinning on its own.
I'm even not sure if the electric choke ever gets turned off.
When the scooter was running fine I could tell if the choke is on when my front panel was vibrating too much, haven't seen it being off this year.

Is it possible that the choke is messing everything up?
It seems really like the choke is the faulty one, because I need to wait a while after the engine has died (enough time for gas to evapurate from the engine).

[Firehawk989]

I think you misunderstood. The idle and a/f adjustment screws are not adjusting the valves. Adjusting the valves involves removing the valve cover from the cylinder head and adjusting the intake/exhaust valve adjustment screws with a feeler gauge. It's actually a fairly simple procedure and will only take you a few minutes after you get through it the first time. Check the service manual for the valve adjustment procedure.