Honda Dio only start if i pull throttle

[kotama]

Hello!

First of all, sorry for my bad english!
I have a Honda Dio 49cc scooter and when i try to start (with cold engine) the scooter wont turn on and run, except i pull the throttle.
When it started and i release the throttle its stall immediately, but if i hold throttle for 1 or 2 minutes then the idle is ok.
If the engine is warm everything is ok, i can easily start the scooter and wont stall. 

The parts i changed:
- new carburetor (aftermarket)
- new by-starter (i checked it works, after 5 mins the pin going out)
- new pump assy (fuel)
- new pump lines, pipes
- new air filter
- new spark

The things is checked:
- spark is ok
- reed valve is ok

air / fuel screw: 2 turn out
idle screw: 2 turn out


One thing i observed, if i turned the idle screw all the way in the scooter started and idled when engine was cold.
Do you have any idea what i need to check?
Thank you!

[pili]

Turning the idle adjustment all the way in replicates cracking the throttle when you start it. You say it has a new carburetor. It sounds like the cold start enrichment isn’t working. Does the carb have an electrical connector for an enrichment needle or does it have a manual choke that decreases air flow?

[kotama]

It has an electrical auto choke what is working, i tested it. If i let warm up the engine the needle goes out from the starting position.

[pili]

You've tried different settings on the air screw? It sounds like it's lean when cold. What's the spark plug look like?

[kotama]

I tried to turn out / in air screw when the engine is warm, but when the engine cools down i have the same problem with starting.
I checked the spark and its black and dry.

[pili]

Black indicates rich. What brand carb? It sounds like the enrichment needle is adding too much fuel. I don’t think it’s adjustable on the stock carb, maybe it is on yours?

[kotama]

The carb is aftermarket noname, it is from Aliexpress, i cant adjust the needle.
I tried with other auto-choker, same results.

Update: If i pull out the auto-choker from carburator, the scooter start immediatly, if i cover the auto-choker hole with my finger, the engine stall.

[aeroxbud]

That is normal. If you remove the choke, or disconnected the wire. The choke will remain on permanently.
When you cover the hole. The bike thinks it's warm and the choke has cut the extra fuel off.

[pili]

Sept 26, 2024 4:39:06 GMT -5 kotama said:

The carb is aftermarket noname, it is from Aliexpress, i cant adjust the needle.
I tried with other auto-choker, same results.

Update: If i pull out the auto-choker from carburator, the scooter start immediatly, if i cover the auto-choker hole with my finger, the engine stall.

Did you let it run a minute to warm up before you plugged the enrichment mounting hole with your finger?