I have a 2004 Sportsman 500 with 155 miles and since new it has leaked fuel from the tube on the bottom of the carb (over flow / drain tube). The dealership has checked the floats and tighten the drain screw on the side of the carb bowl. As a last resort they gave me a new Mikuni carb however it still leaks. The leak amounts to about a pint of fuel every 30 to 35 miles.

Any suggestions would be appreciated ...

 

wow thats alot of gas... and u have a new carb??? well is your intake valve opening enough

 

Sounds like the needle valve that controls the gas into the carb is passing. Probably due to dirt in the valve or the valve is grooved but this is unlikely as it is a new unit. It might also be due to incorrect float level setting. If I were you as this is a new unit I'd let the dealer handle it.

 

Thanks for the replies. The dealer is baffled but thinks maybe the needle and seat on these carbs needs time to adjust or seat so I guess I'll put more miles on it and see if that takes care of it. At least it runs great...

Thanks again.

 

I don't agree with the statement of "needle and seat on these carbs needs time to adjust or seat". If it's leaking in needs to be disassembled and inspected. There are 3 possible fixes, the float needs to be adjusted to the correct level, the needle valve has something preventing it from seating properly, or lastly the needle valve and or the seat is damaged, maybe grooved and needs to be replaced.
My 2 bits.

 

how can this be carb related if it did this on your old one and now its doing this on your new carb????? i dont get it