What is the voltage at the battery posts with the engine running? Ignore the ammeter for now- - - -the needle deflection changes according to the state of charge of the battery- - - -right after startup it will deflect toward the + side, and move back to center as the battery recharges. The only time it should go (-) is if the engine isn't running and the headlights are on, or if the load on the electrical system exceeds the generator output, like maybe high beam headlights, heater blower, and electric wipers on all at once. Check the voltage- - - -it should be 13 to 14.5 at fast idle.
Jerry
