Alternator problem

[Scrambler]

Hi there
I am not sure if my alternator is working or not. I have the idea that the engine hesistates a little when starting up. It used to start on the button. The guage of the alternator is not in the green part anymore but in yellow. I can't adjust it. How do I test if it is working. What could be wrong with it? I am rarely using the truck and it always starts up, including the last month with this possible alternator trouble. I am not sure. Fuel guage is acting weird too; it moves back and forth all the time. (pretty fast)(not the guage but the needle) I am not sure if I use the right names for the parts since my homelanguage is Dutch...

 

[acetomatoco]

The alternator is adjustable for voltage by turning little screw under hex plug on side... However test the output voltage with a good voltmeter any where in the system, even at the batteries, with engine off and then with engine running to see if there is more or less 24 volts not running and 28 volts running... You may have a bad battery.. so test them separately... 12.4 volts not running and charged...check you grounds on the instrument cluster... the four clip dzus fasteners...fuel gauges depend on the tank straps for ground... you may have to run a separate ground wire from the sender to frame... ACE Hook another known good vehicle up to yours with a slave cable and see if your Voltmeter goes into green...A