question about air/fuel screw and pilot jet

[wvspeedfreak]

If you have to turn your air mixture screw all the way in to get it to idle right that means your pilot jet is too large and you need to drop a size correct?

[GPracer2500]

Originally posted by wvspeedfreak
If you have to turn your air mixture screw all the way in to get it to idle right that means your pilot jet is too large and you need to drop a size correct?

That would be true for a fuel screw. With an air screw equiped carb it is the opposite.

http://www.exriders.com/vbb/showthread.php?s=&threadid=229923

[wvspeedfreak]

I just read your attatched post.Very informitve.The carb I am working on is my son's 2 stroke mini which by the way you explained it is an air screw.So evidently I need to go up 1 size.

[GPracer2500]

Yes. On a two stroke carb there is an air screw. The pilot jet flows a fixed amount of fuel and the air screw controls how much air is being mixed with that fuel. If the air screw bottoms out and the engine still runs, your pilot jet is too small.

This shows how an air screw works:
http://www.ducatimeccanica.com/dellorto_guide/fig19.jpg

1 is the air screw
5 is the pilot jet
blue area is air
orange area is fuel
green area is air/fuel mixture