What are the reasons for a scooter making a sizzling sound but failing to start?
3 Answers
The reason a scooter makes a sizzling sound but fails to start is due to issues in the ignition system or fuel supply system. When this happens, it is recommended to check both the ignition system and fuel supply system. The main types of spark plugs include: standard spark plugs, extended insulator spark plugs, electrode-type spark plugs, seat-type spark plugs, pole-type spark plugs, and surface-gap spark plugs, among others. Scooters generally feature a continuously variable transmission (CVT) with an automatic clutch, lacking gear design. Once started, you simply twist the throttle to move, and releasing the throttle will gradually slow down until stopping. Additionally, scooter wheels are smaller than those of other vehicles, and the transmission is mostly belt-driven.
I had the same issue with my motorcycle last time, it just made a buzzing sound but wouldn't start. Focus on checking three key areas: 1. A depleted battery with insufficient voltage to power the starter motor is the most common issue, especially with old batteries struggling in winter. 2. Worn-out carbon brushes or a short-circuited rotor in the starter motor, which will produce a dry spinning sound without power. 3. Poor electrical connections, such as corroded battery terminals or loose motor wires, causing voltage to drop with a buzzing sound when starting. It's recommended to first use a multimeter to test the battery; if the static voltage is below 12.5 volts, it's likely the culprit. If the voltage is sufficient, directly bridge the two thick terminals of the starter relay (be careful not to touch the frame). If the motor spins strongly, the relay is faulty; if it still buzzes, the motor is probably done for. Avoid forcing the start to prevent blowing a fuse.
Having repaired scooters for ten years, this kind of buzzing and failure to start is quite common. The core issue lies in the circuit transmission: somewhere along the line from the battery to the motor, voltage is being consumed. Listen up—a falsely labeled battery capacity can cause this, as can a poor-quality charger that swells the battery; burnt relay contacts reduce the contact area, causing arcing and a buzzing sound when power is applied; worn copper sleeves inside the motor lead to rotor scraping, increasing resistance and turning into a 'whining' sound; and the easily overlooked poor grounding of the main ground wire, where rusted frames result in poor conductivity. During troubleshooting, first check if the battery terminals are whitened, feel the relay with your hand to see if it's hot, and finally test the motor's no-load current—if it exceeds 150 amps, it needs replacement. Remember to also check the rectifier's output voltage, as excessively high voltage can accelerate damage to these components.