"I HAVE A1982 70 HP. MERC 3 CY
"I HAVE A1982 70 HP. MERC 3 CYL. DO I NEED A SPECIFIC TACH FOR 3 CYL. I PICKED UP WIRINGHARNESS FOR TACH. WIRES ARE BROWN ,BLACK, WHITE .MOST TACHS HAVE DIAL ON BACK FOR PULSE SETTINGS. THE WIRES ON THESE TACHS ARE PURPLE, BLACK, BLUE"