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I bought new seals for my sons 2012 CRF150F and cleaned the carb and jets. When I took it apart the bottom adjustable screw on the carb was all the way in seated tight. (I believe the bottom screw is the pilot or air mix screw, top one is larger and is idle adjustment)
I thought that the fuel mixture screw should be 1 1/2 turns out, but when I re-assembled the carb with the mixture screw out, the fuel leaks out the bottom of the carb as soon as I turned the fuel back on?? I thought it was maybe the float, but it isn't. Even with the carb apart and pouring gas into the float bowl alone, the fuel comes out the "overflow". Only way to stop the fuel from coming out was to keep the mixture screw all the way in.

the screw has a new o ring and I tired it with both the new and old o ring and same issue. Is this normal?

The bike is running well, but seems weird to me that there is no adjustment capabilities on an adjustable and accesable screw on a carb like this? Ideas?

If you are positive the float is adjusted correctly , then it sounds like the needle/seat is the issue , that is allowing the fuel to continually flow into the bowl , overfilling it ..... it should not be running out the fuel screw (4 strokes have fuel adjustment screws , 2 strokes have air adjustment screws) Leardriver or Ray , would be the ones that would know what the fuel screw should be at ... hopefully , they can chime in ...

It is the adjustment screw located on the bottom of the fuel bowl in this photo that I am referring to. And since it is at the very bottom of the bowl I don't see how this would limit or allow fuel ratio to change? But I am no carb expert either obviously

But if it is in any position other than fully seated (all the way in) fuel comes out of the drain tube


Thanks

No , that screw at the very bottom by the XJY19612 is the Bowl Drain Screw , if you turn it out (counter clock wise) it will allow the bowl to drain , it is not a air/fuel mixture screw and it needs to be all the way in/clockwise , the mixture screw (fuel screw) is the one located in the red circle

THANK YOU. That makes way more sense