What Causes a Scooter to Frequently Stall When Decelerating?
2 Answers
The reasons why a scooter frequently stalls when decelerating are as follows: 1. Clogged fuel filter screen: Insufficient fuel supply after accelerating causes the engine to stall. After stopping, gasoline flows back into the float chamber, allowing the scooter to restart. However, when accelerating again, the fuel level in the carburetor drops, and the main jet cannot draw fuel, leading to another stall. 2. Clogged carburetor main jet: This may be due to dirty gasoline or long-term inactivity of the scooter, causing fuel deterioration and forming deposits that block the main jet. 3. Engine overheating causing slight cylinder expansion: If the cylinder is expanded, it is necessary to go to a repair shop to replace the cylinder block, piston, and piston rings.
I've seen many cases of scooters stalling during deceleration while repairing vehicles. The most common cause is carbon buildup or blockage in the carburetor, which leads to uneven air-fuel mixture and makes the engine prone to stalling when the RPM drops during deceleration. Additionally, aging spark plugs or faulty ignition coils causing ignition failure are also common issues. I recommend first checking if the air filter is dirty and cleaning it to see if that helps. If not, then inspect the fuel system, such as the fuel pump and fuel lines, for any blockages. Improper adjustment of the idle valve could also be a reason, and some scooters allow you to slightly increase the idle speed by adjusting the idle screw. Ignoring this issue can be dangerous, as sudden stalling while riding—such as during a turn when you lose power—can easily lead to a fall. It's best to regularly inspect these components during weekly maintenance to keep the engine running smoothly.
