So we have a number of these quads in the family. All ’00-’02. We had some issues with one of our carbs leaking gas from the bottom drain hose which to me is indicative of a floater problem. So we cracked it open and found something interesting.

First off the floater pin appears to be sticking slightly, so it isn’t allowing itself to be pushed up to seal with the floaters upward force.
Second, the cause of the problem appears to be from a greenish residue which we can see all over in the lower reservoir. It’s got a chalk-dust like texture and has to be wiped off, it doesn’t just rinse off.

Upon cleaning it all up as best we could in the field, the problem continues, and possibly worsened. Then magically went completely away. Then the leak returned in a slow drip so we parked the quad. It was a weird one to us. The gas was fresh. Quad was running well for quite a while (35km), then after a while would just barely stall out at base idle, but was otherwise running fine.

What do you think that green crud is and is there a simple treatment or cleaning method?
Is there a replacement for: just the floater pin? The bronze tube it slides in/out of? Perhaps the bronze seat or rubber tip are still dirty, preventing a seal.