50cc gy6 won't start without turning low fuel screw By grizzly (Read 457 times)

[grizzly]

Alright fellas, I got a new problem for yas. I've had my scooter running better than it's ever run its entire life thanks to ya'll. BUT, about once a week or after 5-6 rides, I can't get the scooter to start at all, until I give the low fuel mixture screw a half turn to the left, then it fires right up. I'm afraid I'm going to hit the end soon and the screw will pop out. 

Any ideas what causes this?

[trashtruck12172]

you shouldn't have to mess with the air/fuel screw once it's set. the gas cap may not be venting and you're starving for fuel. loosen the cap and see if the problem repeats.

[grizzly]

Thats not it, I left the cap off and it didn't affect it in anyway, vs the half turn which caused it to fire instantly. Does opening the screw a bit cause a little gas to pass on through to the spark plug? I think I should check my plug.

[trashtruck12172]

a good starting point for the air/fuel screw is 2 1/2 turns out from lightly seated. iirc, turning it out more will allow more air than fuel making it run lean but I've been wrong before.