Loadnetwork320

Hi, my 03 400ex recently began leaking gas out of the carb drain even when the drain screw is seated. From reading online it seems like this is always a case of the float/float valve or seat. I disassembled my carb and cleaned it all out thoroughly. I checked to see if the valve would actually seal in the seat while I had it off the quad and it does. The float moves freely, there is no friction it doesn't bind anywhere, it appears to seat the needle at the appropriate time to my bare eye, when the float is down the needle isn't seated and when the float gets up to around level it seats the needle. I don't have a float gauge. there are no obstructions, debris, scratches or anything on the seat. Like I said I hooked up a little vial of gas to a tube and moved the float up and down and it would seal correctly. But once it's installed on the quad I can watch it, just idling, it will leak for like ten seconds, stop for maybe 20, leak for a minute, stop again...When I'm actually riding and it starts it will sputter and stuff as if it's draining too fast to even get into the jet. I tried adjusting the float a tad but I know it isn't really adjustable and don't want to break it. Is there anything else I could try other than clean it again? I wouldn't be posting if I hadn't already cleaned it 5 times with no change. Thanks