Technical Tips; Carburetor; Slow Air Jet - Yamaha 25BMH Service Manual

GEN

TECHNICAL TIPS

INFO
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TECHNICAL TIPS

CARBURETOR

(1) Slow air jet (idling and slow speed operation)
Since the throttle valve is almost closed at low speeds, and thus the vacuum at venturi is
small, air/fuel mixture is not delivered through the main nozzle.
At idling, the fuel delivered from the pilot jet is mixed with the air delivered from the pilot air
jet.
Air and fuel mixed at the rate determined by the pilot screw adjustment, are supplied to the
engine through the pilot outlet located above the throttle valve.
Once the throttle valve is opened to go beyond the bypass holes during the slow-speed
operation, air/fuel mixture is fed through the bypass holes.
Fig. 11
1-15