The left carb leaks fuel out of the two little brass holes on the airbox side of the venturi inlet. The needles and seats are less than a year old. In an attempt to figure out exactly what part was causing the problem, I swapped the seats. The left carb still leaked. Then I swapped the needles, the left carb still leaked. Then I swapped the floats, and the right carb starting leaking. So right now it points to the float. I adjusted the tab to lower the float as much as I could and it still leaks. I don't know if I can bend the tab anymore because it has almost 45 degrees of bend in it already. I took the float out and soaked it in a bowl of water to try to find any cracks. I couldn't find any leaks in the float, and it doesn't sound or feel like there is moisture on the inside of the float. I just replaced all the o-rings in the carbs with brand new units also, so it shouldn't be leaking past those. I also took a clear fuel hose and attached it to the bowl drain. Sometimes the fuel level is right at the bowl gasket level and slowly increases, other times it just jumps right to the bottom of the venturi for the air intake and starts leaking. Besides replacing what appears to be a fully functional float, any suggestions?
I suspect it is the float valve seat. Or the float needle. Inspect them for scratches or wear.
Quote from: Paulcet on December 29, 2009, 09:18:23 PM
I suspect it is the float valve seat. Or the float needle. Inspect them for scratches or wear.
I swapped out the needle (left to right) and the leak didn't move with it, so its not the needle. I swapped out the seat and the leak didn't move with it, so its not the seat.
Oh, sorry. I misread your post. If the floats are equally boyant, maybe the pivot on one is "sticky". Or maybe you have the fuel line attached to the wrong nipple? Buddha, what happens when the fuel line is attached to the vent?
(edited to fix cell phone induced typos)
One thing I did once was put the valve needle in upside down -- it really looked right that way! I don't know what your experience level is, so I'm not sure if that's something you could overlook. Pointy end up...
Quote from: romulux on December 29, 2009, 10:01:04 PM
One thing I did once was put the valve needle in upside down -- it really looked right that way! I don't know what your experience level is, so I'm not sure if that's something you could overlook. Pointy end up...
Lol, pointy end is up. It was working fine for about a year, then after a track day it started doing this. So something about 8K rpms+ for a few hours got the carb to not like me.
Somehting in the seat is holding it open ...
Ran fine and suddenly starts leaking ... clean and check and adjust.
Fuel line to reat top vent hose will totally cause it to leak like crazy from everywhere.
Cool.
Buddha.
I'll give it a try but I don't see how it could be the seat.
OK dont open it yet.
It switched sides with the float swap right - OK I would maybe tap the body of the right carb ... something is keeping it open.
Cool.
Buddha.