Cummins/Onan 15.0 HA / 7.5 HA — Starting Resistor Adjustment (Spec A Only)
Adjustments
For the Cummins/Onan 15.0 HA / 7.5 HA, from the Cummins/Onan service manual.
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Before you start
- Adjust starting resistor in small steps and check adjustments often to avoid cycling (alternate starting and stopping).
Procedure
- If the control will not start the generator set when minimum load is applied, adjust the variable resistor on the terminal board (left side, two wire models).
- Turn the adjustment screw with a Phillips screwdriver clockwise to increase minimum starting load.
- Turn counterclockwise to decrease minimum starting load.
- Adjust starting resistor in small steps and check adjustments often to avoid cycling (alternate starting and stopping).
Tools required
- Phillips screwdriver Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.