Might be a good Idea to drain the float bowls into a clean clear container, to see whats there. Then once drained, with the drains open, place the petcock to Prime. That will flush the float needles a bit. Might rinse off a loose piece, might not. But can't hurt. If stuff is in the bowls, well better go through the fuel system. Clean the tank, Petcock, Carbs, install a in-line filter for a gravity system, and well consider the overflow tubes.