I recently purchased a Teleflex Tachometer for a 1984 Force 125 HP outboard motor model# 1258X4A with the 20 pole connector. I attached the GRD to the bottom black wire terminal and the SEND to the 3rd wire down which was the only white connector I could find (which was recomedned in the manual as the likely "tach" conector if one is not labled). The IGN is connected to the "I" terminal on the ignition switch by way of a lead to the overheat buzzer (I think). The tach goes to "0" when the ignition is turned on as does the fuel gauge. It seems to show about 1500 RPM at idle, then increases as I give it power up to 2000 RPM then begins to go back to "0" as the speed increases further. When I am at wide open throttle it reads "0". Then as I back down on the speed it gradually increases up to 2000 RPM then back to 1500 for Idle. How do I correct the problem? My shop manual wiring diagram does not show a "tach" lead nor is there a "tach" label on the terminal strip. I do see a positive & negative lead to the coil on the diagram but it seems like a sealed unit on the engine. Any suggestion's?
