its posb the fuel line needs replacing. as for the black knob ?, thats a primer bulb, i never use it, its worthless, but they do leak over time. it will need replacing as well.

I have a 2000 trx450 that's losing fuel from somewhere on the carb. Hard to tell exactly where since the whole thing was covered in fuel when I found this problem. When I wiggled the fuel line, there was gas oozing out of where it connects to the carb. That seems slightly abnormal to me but maybe that is how it works all the time? What would be the issue there, is the fuel line worn out or is the clip not holding it on properly? Also, the little black knob underneath the fuel line was leaking gas when I pressed it in. I dont know what it does but that doesn't seem like it's working either... Any thoughts? Thanks

Thanks got this issue fixed

no clue..i don't mess with stock settings, not to mention..i will never own an es model for this very reason !..lol.

Tampons in the gas tank…..LOL!