My motor is older with an unregulated charging system. I installed a tach shortly after buying it, and never had any trouble with the tach, but it would routinely charge at 16-17 volts.

I installed a CDI 193-5114 regulated rectifier to remedy the issues. It worked well for months but began overheating and overcharging (hot enough to actually start melting the potting). I have since moved it off of the engine and mounted it to a heat sink, which solved that problem.

The main issue is that this regulated rectifier really screws with my tach. It will only read up to 4k RPM, and when the battery is fully charged, it nosedives to zero, and generally acts screwy while the regulator is doing it's thing.

The dilemma that I have now, is that I have been playing with props, and it is impossible to judge what size I need without an RPM reading.

The regulator has 5 wires, 2 yellows (stator), battery positive and ground, and a grey tach wire. How could I bypass the regulator to make the tach work? Unhook the stator wires and run the tach wire right to one of them?