Walbro WYK Carburetor Repair And Service
Walbro WYK Carburetor Manual and Parts List for the correct identification, repair and service of the WYJ series carburetor found in trimmers and blowers. View free online images or download the full Walbro WYK Carburetor Manual PDF which can be printed or saved on any suitable device. Clear diagrams and information to help in parts ordering or repair of this Walbro WYK series carburetor. Identify all component parts of the Walbro carburetor.
Walbro WYK Carburetor Manual
The Walbro model number is stamped on the body of the carburetor.
WALBRO WYK AT START POSITION (PURGE)
By depressing the purge bulb, the air is forced through the umbrella styled check valve. This air passes through the pump body and out the overflow tube.
When the bulb is released, the umbrella check valve is drawn closed. An orifice bypassing the check valve allows fuel to be drawn up from the fuel tank, thru the carburetor fuel pump, metering chamber and into the primer bulb. Once the primer bulb is at least a quarter full filled with fuel, the engine is ready for the starter button to be pressed and the engine to be started.
STARTER BUTTON (PRIME)
Some WYK carburetors are equipped with a starter button. This button, when depressed for 3-4 seconds, forces fuel from the fuel pump of the carburetor into the nozzle for easier starting.
WALBRO WYK STARTING PROCEDURE
Depress purge bulb 4-5 times until fuel drains out of overflow tube.
Depress starter button for 3-4 seconds to allow fuel to flow into the nozzle.
Hold throttle open part-throttle or wide open and pull starter rope until the engine starts.
WALBRO WYK AT IDLE POSITION
The barrel styled WYK carburetor adjustment at the idle position is similar to all Walbro barrel carburetors. A boss on the throttle bracket allows the throttle lever to create a ramp effect going from idle to wide-open throttle. Idle adjustment is done with the inner idle needle located below the plastic plug. Note that when all idle adjustments are complete the plastic plug must be reinstalled.
WYK IDLE ADJUSTMENT PROCEDURE
1. Remove the plastic plug located directly above the inner idle needle.
2. Using a 2.5mm wide flathead screwdriver, turn out the inner idle needle until threads disengage.
3. Turn inner idle needle clockwise 10· 12 turns in very slowly. The idle RPM will Increase (lean) until the peak lean idle RPM is obtained. Once this is obtained, turn inner idle needle counterclockwise (rich) until optimum idle is obtained. Please note that carburetors and engine applications will vary therefore the needle settings may vary also.
4. Adjust the idle speed screw to the correct idle RPM.
5. Check idle, progression and wide-open throttle.
NOTE: Some WYK carburetors are manufactured with a high-speed needle. See instructions.
WALBRO WYK AT WIDE OPEN THROTTLE POSITION
When the WYK carburetor is at the wide open throttle position, the throttle lever will be at the highest side of the ramp. This will allow the idle needle to be pulled away from the nozzle outlet and allow enough fuel to be fed to the engine at W.O.T. The barrel will be fully open allowing as much air as permitted to enter from the choke side and flow into the engine.
WALBRO WYK CARBURETORS WITH A HIGH-SPEED ADJUSTMENT NEEDLE
Some WYK carburetors have a high-speed needle to adjust the fuel flow delivered to the nozzle. High-speed needle adjustment should be set between 1 1/4 turns open at the engine manufacturer’s specified RPM.
High-speed needle adjustment should be done after the idle needle setting procedure is complete. Pre-set the high speed to 1 1/4 turns open to insure an initial rich setting.
Walbro WYK Carburetor Manual and Parts List PDF
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