Riding lawnmowers use a starter system designed to power up the motor for a quick start to blade operation. This is not the same as the ignition system for a car, which is more likely to use ignition coils to generate voltage. A mower starter tends to use a simpler battery and solenoid system to create the necessary spark to ignite fuel in the engine. Problems with this system can indicate several different issues.
The solenoid itself is a small device in the starter, a looped coil of wire that is designed to quickly transmit current from the lawnmower battery to the engine spark plug. If the solenoid is damaged, it will not complete the current circuit and cannot draw power from the battery. The connections between the battery and solenoid may also be corroded or dirty: cleaning them might solve the problem if the solenoid registers a proper current on an ohmmeter.
Battery Issues and Similar Problems
If the solenoid appears to be working correctly, the problem may be located close by in other parts of the starter. The battery may be corroded or dead itself. A new battery might solve your starting problems. The starter switch that the battery uses to begin ignition may also have failed, and will need to be replaced if it tests faulty.
Your riding lawnmower depends on a properly wired ignition system. If the engine does not start or is difficult to start, and you have avoided common issues like a flooded engine or clogged fuel line, the problem may like in the ignition wiring, which may have failed to transmit signals to the solenoid at all. Sometimes the ignition switch has been accidentally turned off, and sometimes ignition timing with fuel injection is poor. Adjustments and replacements can fix most of these wiring difficulties.
Spark Plugs and Engine Issues
Your solenoid and starter may be working correctly, but the engine itself may be having problems. The deadman switch, designed for protection, may have become stuck open so that the fuel cannot combust. The spark plug that the engine uses to transfer the current from the starter battery may have burned out or become damaged, so the spark will not transfer. Again, repairs and replacements can help solve these problems.
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