Carburetor: Hard starting / stripped mixture screw/ bad vent lines

[tbyte]

Was having much harder than normal starting problems from this past winter through the June despite new batteries.  I suspected it was the stripped mixture screw I had left undone when I rebuilt carbs.  One cylinder ran very rich, mpg suffered and I got many complaints about the stench.  When humidity was >90 % she would not start at any temp w/o pre-heating spark plug.                                        I finished replacing the starter motor I burned out and pulled the carbs this pm.  Carbs are here on desk and a couple of the vent lines are in sad shape.  Could that be a/the cause of hard starting?  Should they be replaced or will duct tape suffice?  I was going to ask if it safe to heat up stripped mixture screw but I can not get any bite on it so I will just drill it out.

[Howie]

Replace the vent lines.  Yes, they possibly could have been your problem.  Your stuck idle screw could only be a problem at or slightly off idle, but I doubt it.  Good luck on freeing the idle screw.  A little heat might help, but be careful.  You don't want to melt any internal parts or warp anything.  I would probably stay away from heat unless I was going to buy new bodies anyway. 

[Langanobob]

Can you post a picture of the carb, showing the stuck idle screw head?  Maybe someone here can come up with a fix.   Drilling them out is tricky.

[tbyte]

Will do on vent lines, thanks.  I tried drilling last night with left hand bits hoping it would back out stuck to the bit; no go.  Next I will try to break it up and tap out the pieces.  I can always go to a machine shop and if I do damage the threads I have a spare carb I bought on ebay. 

[tbyte]

I put bike back together yesterday evening but while it would fire with the fuel I sprayed into carb it would not start.  I am thinking I misrouted the fuel line.  But my question is about turns of the idle mixture screw.  I did the standard 3 turns but is a turn 180 or 360?  I have to pull airbox anyway.  Thanks.

[Howie]

A full turn is 360^o.

[tbyte]

Thanks again Howie.  I had done it correctly but she was not starting and paranoia bit me.  Turns out there was no other way to route fuel line, the float bowls were full and I pulled airbox for nothing.  A passerby recommended I alternate fuel and carb cleaner between cranks until it runs.  It worked.  Starting greatly improved closing the holes in the vent line.
    Anyway, she was idling very fast and the mileage was < 25/gal.  I pulled the plugs: the vertical plug was good and the horizontal was wet and oily.  When I was reassembling the carb the float holder came out.  The part that attaches the float to the carb body.  I had a difficult time re-seating it.  I am thinking it has to be the float but I was hoping for alternatives.