KYMCO Downtown 300i ABS, Service Manual, Page: 243 / 263

20
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EVAPORATIVE EMISSION CONTROL SYSTEM
Downtown 300i ABS
EVAPORATIVE EMISSION CONTROL SYSTEM FUNCTION
FOREWORD:
The Evaporative Emission Control System is abbreviated to E.E.C. System. This device collects
the fuel vapor from the fuel tank and then the fuel vapor is drawn into the engine for re-burning to
avoid air pollution caused by the fuel vapor diffused into the air.
FUNCTION
Item Purpose Function
Purge Control Valve
Control vaporized HC from
fuel tank not to diffuse into
the air.
The charcoal canister absorbs vaporized HC
from the fuel tank. When the engine is
running and the purge control valve is open,
the fuel vapor in the charcoal canister is
drawn into the engine for re-burning.
Charcoal Canister
Absorb and store the
vaporized HC from the fuel
tank and carburetor. The vaporized HC is absorbed in the charcoal
canister and the specified volume of HC in
the emission should not exceed 2g.
P.C.V. System
Completely recover the HC
from blow-by gas in the
crankcase for re-burning.
Through the P.C.V. system, the blow-by gas
from the crankcase is separated into fuel
vapor and fuel and then drawn into the
cylinder for re-burning.
TROUBLESHOOTING
Engine loses power or runs erratic at idle speed
1. Clogged P.C.V. system
2. Clogged air cleaner
3. Faulty purge control valve
4. Loose or broken E.E.C. system tubes
Engine idles or accelerates roughly
1. Faulty fuel cut-off valve
2. Faulty purge control valve
3. Clogged or faulty charcoal canister
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