What are the causes of starter motor spinning without engagement?
2 Answers
The causes of starter motor failure include the following points: 1. Malfunction of the solenoid switch. 2. Broken teeth on the drive pinion or severe wear on the flywheel ring gear. 3. Slippage of the one-way clutch. 4. Damage, misalignment of the starter motor shift fork, or detachment of the linkage hook. 5. Issues with the fit between the armature shaft and armature core inside the starter motor. Here is additional information: 1. Common faults of the solenoid switch generally include open circuit, short circuit, or grounding of the pull-in and hold-in coils, as well as burning of the contact disc and contact surfaces. 2. Check for open circuits or grounding in the coils by measuring resistance with an ohmmeter. If the coils are faulty, rewind or replace them. 3. For minor burning of the contact disc and contact surfaces, they can be repaired with a file or sandpaper. Replace the return spring if it is too weak.
I've encountered the starter spinning freely several times, which is common in older cars. The reasons include the starter's pinion gear being broken or severely worn, unable to engage with the engine's flywheel; the solenoid switch aging and getting stuck, failing to push the gear out, resulting in free spinning; or the flywheel ring gear having broken or missing teeth, which is more common with long-term frequent starts. On the electrical side, issues like relay failure or loose power cables can cause weak current, unable to push the gear. Mechanical jamming is also possible, such as sludge buildup or rusted components. If not repaired promptly, it can exacerbate wear or even damage the flywheel, so I recommend avoiding forced starts and quickly taking the car to a repair shop to check the gear set and electrical circuit. Regular maintenance, such as lubricating related components, can extend their lifespan.
