Trojan Boat Forum

im having the same problem. Where is the external regulator to check this?

Better late than never....

The voltage regulator is located under the black cover near the ignition module and passive resistor. RPM jumping is a common symptom from faulty alternators.

I had a problem with mine, not so much jumping around as drifting, within a range of about 400-500 RPM of what I was actually turning. Turns out all I had to do was turn the selector switch, located on the back of the tachometer, back and forth between cylinder settings a couple of times and just like that no more problem. I guess the internal contacts must have been tarnished.