I had a fuel tank issues this weekend when I started the motor for the first time of the season. The anti-syphon valve on the top of the tank had corroded in half and the fuel line fell off. Fixed that but the top of the sending unit was badly corroded also so I bought a new one. The old sending unit had a red wire connected to the center post and a ground wire on the flange. There was also a black wire about the same length as the other 2 that was tie wrapped with them. The black wire had a female bayonet type connector that was connected to a short piece of the mating male connector, but not attached to anything. I couldn't see anything that it might have originally been connected to and the fuel gauge was working before I started working on the top of the tank. Any thoughts on where this black wire came from. Do some sending units require 3 wires? The replacement only needs 2 (red and ground).