What does the fuel system consist of?

Fuel tank - Stores fuel, usually less than 5 liters on a 50cc scooter. Fuel tanks are made of plastic, which has almost displaced the steel used until recently. They are installed in various places. Previously, they were mounted directly under the front of the seat, but most modern scooters have the ability to store the helmet there. Therefore, the tank is moved to the "tail" part of the scooter, lowered below the luggage capacity or placed at the front. The tank lid has an opening through which air enters the tank as the fuel is consumed. On many scooters, the tank lid is sealed, and the inside of the tank is ventilated through special activated carbon tanks that absorb gasoline fumes.

Fuel pump - This is not used on all scooters, because on most models, the fuel tank is above the engine, and fuel flows by gravity through a hose to the carburetor. On scooters with four-stroke engines, the fuel pump is electrically driven. Scooters with two-stroke engines have vacuum-driven fuel pumps - similar designs are commonly used in outboard engines. They take advantage of the pressure pulsation created in the crankcase as the piston moves.

Fuel faucet - An essential part of the power system, as it prevents fuel from leaking through the carburetor when it is stopped if its float valve leaks. Motorcycles and old models of scooters used a fuel faucet with manual control.

This tap has three positions:

• "3" or "Off" - closed;
• "O" or "On" - fuel from the main tank volume;
• "P" or "Res" - fuel from the reserve tank.

In case of a long stop (for example, overnight), the driver closes the faucet. After starting the engine, it switches back to the normal "open" position. If the engine stops during the trip, the driver switches to the reserve position and drives to the next refueling point. Usually the reserve capacity is such that you can drive 20-30 km on it.

Air filter - It is used to filter the air entering the carburetor from dust and other foreign matter. The air filter is an important part of the scooter and ensures the longevity of the engine. It also acts as an intake noise suppressor. The air filter consists of a housing with a cover and a cartridge.

Different types of filters are used in modern scooters:

• paper
• made of polyurethane foam (foam rubber)
• mesh filters.

Paper filters are disposable, that is, they are replaced at each service. Foam filters allow repeated washing, followed by impregnation with special oil. Whichever air filter is used, it should be cleaned regularly, monitored and replaced if necessary. A faulty filter lets solid dust particles into the engine, causing accelerated wear of the piston, cylinder bore, connecting rod bearings and crankshaft. An excessively dirty filter impedes air flow, enriching the fuel mixture, reducing power and increasing fuel consumption.