Remove the generator cover and panel, and check whether the wiring is loose or whether the cable rubs against the rotor.

Remove the carbon brushes and check whether they are damaged or whether the contact areas of the brushes are dirty.

Check whether the AC power output switch is damaged.

Check whether the positive and negative wires on the carbon brushes are connected correctly.

Replace the automatic voltage regulator (fan-type AVR) and observe whether it is damaged.

If there is no DC output, check the wiring connections, or replace the rectifier-regulator and observe whether it is damaged.

If the electric-start circuit is not charging, use a multimeter to check whether the brown charging-coil lead on the starter cover has voltage output.

If the electric-start circuit is not charging, remove the panel and use a multimeter to check whether the two wires connecting the rectifier-regulator to the charging line have power.

If the electric-start circuit is not charging, check whether the electric-start switch is damaged.

If the electric-start circuit is not charging, check whether the polarity of the red and black wires is reversed; if so, remove the panel and swap the two wires connected to the rectifier-regulator.

If the generator output voltage is high or low, remove the automatic voltage regulator (fan-type AVR), adjust its small painted screw on the back, and after adjustment, repaint the screw threads to prevent voltage changes caused by screw loosening.

If the generator cannot be shut down, check whether the shutdown switch is damaged and whether the engine and generator grounding points are in good contact.

If the electric starter cannot start, first check whether the battery charge is sufficient, whether the electric-start switch is in good contact, and whether the electric-start switch is damaged.