BR-340 Leaf Blower question

w0slOctober 30, 2010

I have a Stihl BR-340 leaf blower and have had what appears to be a carburetor problem. Fuel is getting to the carb, new spark plug, etc. It starts but runs a bit rough. The instructions in the owner's manual are not clear on making adjustments to the Low Speed (L) adjustment screw or even whether it takes a special tool to make the adjustment. The manual just states, "Carry out standard setting on the low speed screw." What the heck does this mean. It is not described anywhere in the manual. Any help would be appreciated.

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W0: Some of Stihls carbs have limiter caps , others welch plugs limiting only adjustment of the High Speed and Idle Screws. Hopefully your unit has no restriction within these adjustments. My advice would be to remove both Hi & Lo jets and spray carb cleaner within the orifices. Also add some concentrated carb cleaner within fresh fuel approx 2 ounces. Let mixture sit 20 minutes then replace the jets and turn in the jets until they bottom (gentley) then turn both out 1-1/4 turns . Choke the carb and attempt starting as usual . Once you have it started keep it running until the saw will run without choke . Once warmed up adjust the low speed in or out till it will accelerate without hesitation . As for the Hi speed same procedure , normally I turn the screw counter clock wise to around 1-1/2 turns
at WOT until it begins to diesel or gallop then turn it in )leaner) just till it clears out . Once all this has been done you can set your idle speed to your liking . I usually set mine a little high to assist with Cold Starting and Idle . Remember any adjustments (Hi or Low) normally require readjustment to the Idle setting .

Note: Just a further note of info always ensure your fuel tank is full and your air cleaner clean before attempting any carb adjustments ...E .

    Bookmark   October 31, 2010 at 9:00AM
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Thanks E,

My leaf blower has both the Hi and Lo adjustments limited to only a quarter turn by plastic plugs so I can't remove them. It appears that the plugs are plastic with a screw driver slot in them and a small hole in the middle. I was afraid to try to force them past the stop, thinking there must be a way of removing them without breaking them. Do you know if this is possible?

    Bookmark   November 1, 2010 at 12:20AM
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