Walbro WYA Carburetor Repair And Service
Walbro WYA Carburetor Manual and Parts List for the correct identification, repair and service of the WYA series carburetor found in trimmers and blowers. View free online images or download the full Walbro WYA 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 WYA series carburetor. Identify all component parts of the Walbro carburetor.
Walbro WYA Carburetor Manual
The Walbro model number is stamped on the body of the carburetor.
WALBRO WYA AT WIDE OPEN THROTTLE POSITION
With the WYA at the wide-open throttle (w.o.t) position, the throttle lever will ride to the highest point on the lever. This will allow the idle needle to pull away from the nozzle outlet and allow enough fuel to flow into the engine at w.o.t. With the throttle valve fully open, the max. amount of air is allowed in through the lower throttle bore.
The upper throttle bore allows air to flow into the combustion chamber via the stratified scavenging port. This “air only” charge allows for clean exhaust emissions by blocking the transfer port’s fuel from being swept into the exhaust stream.
WALBRO WYA AT IDLE POSITION
With the throttle valve at the manufacturer’s preset adjustment, the engine is allowed the correct fuel and air it requires at the idle position. The inner idle needle is preset to meet the engine and federal emission regulation requirements. The needle is and should always be covered to limit its access and adjustment. No idle needle adjustment is provided on the carburetor the original engine came with.
WYA IDLE ADJUSTMENT PROCEDURE WHEN ADJUSTING REPLACEMENT CARBURETOR
1. Before starting the engine, remove limiting device (glue) from the top of the inner idle needle.
2. Using a 2.5mm wide Flathead screwdriver, turn out the inner needle until threads disengage.
3. Turn inner idle needle clockwise 10 turns from thread engagement.
4. Start engine.
5. With the engine in the idle position, continue turning the inner idle needle clockwise. The RPM should increase (lean) until the peak lean idle RPM is attained. Turn inner idle needle counter-clockwise (rich) until optimum idle is attained.
6. Reinstall limiting device (ball or glue) to limit access to the inner idle needle.
Note: Original Engine Manufacturer’s engine adjustment/operation specifications must be maintained.
Walbro WYA Carburetor Manual and Parts List PDF
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