have a 1984 Evinrude 90. Recently put on OMC Throttle Controller and wire harness. The throttle has a 3 pin plug for the tach (purple,black,grey) and the OMC System Tach I got on eBay has an 8 pin plug. I pulled pin 1,2, & 3 out of the 8 pin plug and plugged them into the 3 pin tach plug. My...