I am going to be buying a 1986 Sea Ray 300. The boat originally had twin 260s in it. A swap to crusader 270s was started. The motors were gone over. And installed. What is yet to be done is the risers and manifolds need to be installed, and the wiring harness. Here's my concern. The mechanic that was working on it said that harness for the mercruiser has an extra wire. Anything else on a motor, I can handle, but me and wires don't get along well. This is a pretty common swap I'm sure, everything else was pretty much the same. He had to have a bracket made up in order to mount the heat exchangers, but other than that everything pretty much went right in. Anyone know what I'll have to do with this harness ? Is it just an extra gauge or something ? The motors are 91 crusader 270s I believe. Thanks.