Walbro WYJ Carburetor Repair And Service
Walbro WYJ 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 WYJ Carburetor Manual PDF which can be printed or saved on any suitable device using a PDF reader. Clear diagrams and information to help in parts ordering or repair of this Walbro WYJ series carburetor. Identify all component parts of the Walbro carburetor.
Walbro WYJ Carburetor Manual
The Walbro model number is stamped on the body of the carburetor.
WALBRO WYJ AT START POSITION (PURGE)
Some WYJ carburetors have as an option a purge system. This purge system allows the customer to purge the metering system of air and replace it with fuel tor easier starting.
WALBRO WYJ STARTING PROCEDURE
By depressing the purge bulb 4-5 times, the air is forced through the umbrella check valve. This air passes through the pump body and out the overflow tube. Each time 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, through the carburetor fuel pump, metering system and into the primer bulb. Once the primer bulb is at least 1/4 filled with fuel, the engine is ready tor the choke position and the engine can be started.
WALBRO WYJ AT IDLE POSITION
The WYJ carburetor has two idle adjustment design options. Option 1 allows for the inner idle needle to be adjusted and a white plastic cap placed on top to hide the needle. Option 2 is with the same inner idle needle but also has a black idle screw located above the needle for a fine-tune adjustment. Please read the following instructions for correct adjustment of the WY J at the idle position.
WALBRO WYJ IDLE ADJUSTMENT PROCEDURE (WYJ WITH PLASTlC PLUG)
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 very slowly.
4. Start engine.
5. With the engine in the idle position, continue turning the inner idle needle clockwise. The idle RPM should increase (lean) until the peak lean idle RPM 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 setting may vary also.
6. Adjust the idle speed screw to the correct idle RPM. Check idle, progression and wide-open throttle. shut off the engine.
7. Reinstall the white plastic plug.
WYJ IDLE ADJUSTMENT PROCEDURE (WYJ WITH IDLE SCREW)
1. Start engine and place throttle in tile idle position.
2. The black idle needle is preset to a 1 turn open setting. Adjust this needle to a good optimum idle setting.
3. Repeat step 6. and shut off the engine.
NOTE: Do not attempt to adjust the inner idle needle. It is glued into place and should not be moved.
WALBRO WYJ AT WIDE OPEN THROTTLE POSITION
With the WYJ 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 to be led 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.
Fuel at the wide-open throttle position enters the nozzle thru a pressed in the main jet. This main jet is selected by Walbro Engineering to match the performance of the engine. Based on your altitude or performance requirements, you may have to replace the jet with an appropriately sized jet.
Walbro WYJ Carburetor Manual and Parts List PDF
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