Walbro HDA Carburetor Repair And Service
Walbro HDA Carburetor Manual and Parts List for the correct identification, repair and service of the HDA carburetor. Commonly found in chainsaws, view free online images or download the full PDF which can be printed or saved on any suitable device using a PDF reader. Clear diagrams and information to assist in parts ordering or repair of this Walbro carburetor. Identify all component parts of the Walbro carburetor.
The Walbro model number is stamped on the body of the carburetor
IDLE ADJUSTMENT OF Walbro HDA Carburetor
NOTE I: With the engine at the idle position the carburetor feeds fuel thru the primary idle hole. The second and third idle holes act as air bleed holes to mix with the fuel to create the correct air/fuel ratio.
NOTE II: Both high speed and idle adjustment needles are pre-set by the engine manufacturer and should only be readjusted by an authorized Walbro service person.
WITH BOTH NEEDLES SET AT 1¼ TURNS OPEN PROCEED AS FOLLOWS:
1. Start the engine and adjust idle speed screw (not idle needle) so that engine idles at a moderate speed slightly slower than clutch engagement.
2. Turn the idle needle clockwise (lean) until the engine idles smoothly.
3. Readjust speed screw to correct engine speed.
4. Continue turning the idle needle clockwise until a decrease in idle RPM is evident. STOP.
5. Turn idle needle counterclockwise (rich) until optimum smooth engine idle is obtained.
HIGH-SPEED NEEDLE ADJUSTMENT
With the engine at the high-speed position, the manifold vacuum draws the majority of the fuel from the carburetor nozzle.
WITH BOTH NEEDLES SET AT 1 ¼ TURNS OPEN PROCEED AS FOLLOWS:
1. With the high-speed needle set at 1 ¼ turns open the engine should be running at a slightly richer than normal high speed. Some engines will give a 4-cycling sound.
2. With the engine running at high-speed tum the high-speed needle clockwise (lean) until the engine runs smooth or into a 2-cycle sound.
3. Optimum adjustment is obtained when a very slight 4-cycling sound is heard.
Walbro HDA Carburetor Manual and Parts List PDF
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