What Causes Weak Starter Motor Operation?

[Lorenzo]

Reasons for weak starter motor operation are as follows: 1. Insufficient battery charge or loose/poor contact in the starter circuit wiring connections. 2. Poor contact between brushes and commutator, or partial short circuit in the motor winding. 3. Stiff rotation of the motor shaft or excessive resistance caused by overly tight engine belt installation. Diagnosis and troubleshooting methods for weak starter motor operation: 1. Check battery capacity and the connection status of power cables. 2. If the battery capacity is confirmed sufficient with good circuit connections, use a metal strip to bridge the two main terminals of the starter solenoid switch. If the starter operates strongly after bridging, it indicates poor contact between the main contacts and contact disc within the solenoid switch. If the starter remains weak, the motor itself may be faulty. 3. After engaging the starter switch, if there's continuous "clicking" sound from the starter: When bridging the solenoid's two main terminals results in normal starter operation, this indicates a short circuit or open circuit in the solenoid's holding coil.