I bought a new voltage regulator for my Johnson GT 150 (model J150STLCDC). The part number for the regulator is 395204. When it came in it had only 4 wires on it, my old one has 5. After checking it out the new one is missing the purple wire. It says on a peice of paper that came with the new one due to improvements the purple wire is no longer needed. Also the part number on the old is 583268, my local marine shop said 395204 would work. Is this correct. Also what do I do about the purple wire. I think the grey is the RPM wire, am I correct.