How do I adjust the carburator?
There are two needle screws that can be adjusted to make the engine run properly. Be certain that the carburetor is clean and the diaphragm is in good condition, and the fuel is new. The two needle screws mentioned above should initially be adjusted at one turn open from turned in all the way (lightly seated). Each of these needle screws performs different functions. One is for idle and throttle response (this screw is marked "L" and the other screw is marked "H". L and H are marked on the carburetor body and also on the plastic "shroud" near the adjustment screws. These screws are not interchangeable, being foolproof since the thread sizes are not the same. When properly adjusted the low speed screw (L) allows the engine to idle properly and throttle response will work properly. When the high speed screw is adjusted properly the engine will have correct power at full speed. Adjust the low speed screw so that the engine idles and when you squeeze throttle all the way to wide open the engine should not hesitate and should come up to full speed and when you drop the throttle it should idle nicely without stalling. Now adjust the high speed screw. Hold throttle wide open, holding it there while you adjust the high speed screw. If this scares you (be carefully so that the spinning chain does not cut you!) you may adjust the high speed screw at idle, turning it just slightly in or out. The high speed screw should be adjusted so that the engine does not run clean at wide open throttle but sputters slightly, slightly adjusted open from running clean to slightly sputtering. When under load (cutting a log) the engine should run clean. Good luck!
May 21, 2012 |
Husqvarna , No.455 Rancher, 20" Gas -...