The tach is not working on the '97 summit 670 that I purchased this summer. I have the manual and if I'm reading the wiring diagram correctly the tachometer is fed by the voltage regulator? So far I've tested the wires down from the cowling to the tub- I even replaced that section with a spare from another machine and it didn't work. I plugged in another tach from my old 670 and it didn't work. The light works and the charging system seems to be charging my battery so the Magneto is working. The wires under the engine seem to check out with my ohm meter. Where should I look next? Is the voltage regulator under the engine on this machine? Does it run the tach?