Hello all. I need an expert here. Was talking to my friend who does marine electrical work, but usually not on the motors. 1990 Johnson 200 hp. My friend was trying to get the tachometer to work and found that there was no electrical pulse on the gray wire coming from the rectifier regulator. He believes it needs to be replaced for the tach to work. I just replaced the VRO pump and tested to make sure it was pumping oil. Used my premixed tank to run the engine and a clear hose with oil so that I could see the oil level drop or pulse through the pump. That was working fine. My friend seemed to think that the oil part of the VRO pump had a seperate oil pump in the unit and was operated by the pulse coming from the gray rectifier regulator and tach wire. IS THIS TRUE? I don't believe it to be true. I believe it all to work from the pulse coming from the pulse valve in the engine. Nothing electrical. The reason I'm asking is that if the regulator is not sending an electrical pulse, according to his theory, the VRO pump won't be able to regulate the right amount of oil at different RPMs. Crazy theory I know. But I don't want my customer's engine to lock up! Also, The new pump came with a 4 wire connector. The engine harness has a 3 wire connector. The extra wire is purple. What is the purpose of the purple wire? I extended the wire and screwed it to the purple terminal on the terminal board under the power pack. Is that right? Thank you for any help here! 