# Stihl BG85 WOT problems



## craigschoice (Nov 18, 2006)

Hey everybody! :wave: New to forum. My leaf blower is losing power at WOT. I have cleaned carb & replaced spark plug. Adjusted high speed screw and had no change at WOT. What else can I do? Should I replace fuel filter? I would think if fuel filter problem it would be through entire range of throttle? Thanks


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## madmanmoose (Aug 26, 2006)

loosen the muffler then test it if it runs better remove muffler and clean out the spark arrest screen or outlet it may be clogged with carbon


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## craigschoice (Nov 18, 2006)

Thanks Madmanmoose, I will give it a shot.


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## craigschoice (Nov 18, 2006)

Looked at spark arrestor and it was clear. Should I rebuild carb?  I took it apart and I did not see any tears in diaphrams. Anybody have any ideas on what I should do next? Thanks :wave:


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## hankster (Jan 1, 1998)

Does it sound like it's rich (runs rough) or lean (running out of fuel)? I would first suggest you try adjusting the carb before you start tearing things apart.


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## geogrubb (Jul 28, 2006)

Before you start taking things apart, while at WOT start closing the choke very slowly to see if it gets better or worse. If it gets better you have a fuel restriction, start by replacing the fuel filter, if it gets worse lean out the high speed adjustment. If the blower was running fine while in your posession(you didn't obtain it with this problem)then you should know the history of all adjustments and can undo them. If not I would suggest you get a new diaphgram and gasket kit, soak the carb in a good carb dip type cleaner per labeled directions, then use some compressed air or brake parts cleaner(it doesn't leave residue) to blow out all passages, put it back together and go from there. I thing the BG85 has a Zama carb, however, they use several different models on the Stihl blowers and have different specs for the metering arm so if yours has not been replaced from factory it is already set right. If you're going to get into this big time get ZAMA part# ZT1 which has the meter settings for all their diaphgram carbs, it's about $1.50. Have a good day. Geo


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## craigschoice (Nov 18, 2006)

Thanks guys. I tried adjusting the carb but made no difference in running. It does sound like it is running out of fuel at WOT. I will try and close the choke at WOT and see what happens. Thanks


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## smokestack (Nov 30, 2006)

Well What Happened?


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## big ed (Jul 29, 2006)

make sure the fueline has not deteriorated in the tank even a small hole will cause these symtoms


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