GENUINE Blur 150, Service Manual

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SLOW SYSTEM
This system supplies fuel during engine operation when the throttle valve is closed or slightly
opened. The fuel from the float chamber is metered by the pilot jet where it mixes with air
coming in through the pilot air jet . This mixture, rich with fuel, then goes up through the pilot
passage to the pilot screw . Part of the mixture is discharged into the main bore through bypass
ports . The mixture is metered by the pilot screw and sprayed into the main bore through the
pilot outlet port .
COASTING ENRICHMENT SYSTEM
The coasting enrichment system is included in the slow system. At the normal running operation,
Joining of the air from upper part of then carburetor inlet side to pilot air passage which obtains
proper fuel/air mixture ratio. But if the throttle valve is closed suddenly, a large negative pressure
generated in the cylinder which is applied to the diaphragm . The valve which interlocks with the
diaphragm closes an air passage , thus, the fuel/air mixture ratio by controlling air flow in the
pilot circuit.