Stihl BG55 trouble

viperv10

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Oct 7, 2016
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Hi guys, Iv'e never been on this forum before but have used the Lawn Boy one a few times.
I have a 2 year old blower that is hard to start. It is really cold blooded. Some times it takes thirty pulls to get it going. I never had any problems with my old Stihl. I haven't figured out the right way start it yet. What it is doing now is after pulling my arm off it will idle but if I give it any gas to rev it up it bogs out and dies. Last year it would start and I would have to let it idle for 3 or 4 minutes before I could rev it up. Now if I give it any gas it dies. I can not find my manual, so I'm not sure how to adjust the carb. Now it will only idle for about 10 seconds at the most and then dies. I was wandering if anyone could help me out with this problem? Thanks a lot.
Jerry
 

upupandaway

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viperv10, These are the steps i would go through:

confirm spark and pour a little gas into the carb and try. It running a second or two will tell u it is not the motor the prob but likely fuel prob.

then..

Of the two fuel mix screws, they are on the top of the carb - 90degrees from the primer button. Two screws next to each other, the one closer to the air filter turn it CCW 90degrees and see if there is a difference. Adjust more if u see a difference. Thing is, you shouldn't have to adjust it much unless something else is out of whack even 90 degrees is kinda excessive if everything is good. Make sure to keep track of how many turns turn them back to where u started if all doesn't work.

If no major difference or keep turning the screw makes no difference,

The fuel hose connecting to the carb away from the primer button- disconnect it from the carb and press the primer until fuel comes out of the disconnected hose. When it comes out, stop priming and wait to see if the fuel goes down or doesnt come up at all. Go down\none comes up = some leak in hose\cap\or grommet where hose goes into tank\leak in rubber primer or carb prob. if fuel comes up and stays up, A-OK.

if still no....

I would do this last because it would require more taking apart - KISS(keep it simple s..).
On the carb opposite side from the black plastic piece holding the primer is a plate held on with 1 screw. remove that plate and look for a circle about 5/16?? diameter in the main body of the carb. In this "hole" is a filter screen. Pull it out - this may be clogged with dirt.

I say these would be the most likely places to check. While there are others like leaking shaft seals, clogged muffler, + others, etc. the blower is fairly new so i would think very very unlikely...
 

066

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Oct 18, 2012
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clogged muffler, check the spark arrester to see if it has blocked up with carbon
 

nhyrum

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May 29, 2017
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If tuning the carb and all the above don't work, you may have varnish build up in the carb itself.

As for the adjustment screws, there are two next to each other. The one closest to the air box is the low speed or idle mixture screw, the one closest to the cylinder is the high speed or wide open throttle mixture(and everywhere inbetween) It could be that the high speed screw is either too rich (screwed out too far) or too lean (screwed in too far) my bet is it's too lean. You may want to adjust the low screw to be richer(screw it out, it's the one closest to the air box) Just a teenie bit, 1/8 turn, maybe less, Just to have a little more fuel available so the engine has the fuel it needs to receive.

So, to recap my long winded speech, try assisting your mixture screws, but remember how much you turned them. A paint pen will help.

If that and cleaning/removing the spark arrestor doesn't help, you likely have build up in the carb restricting flow, which is common when fuel sits for a long time in a carb. Either disassemble and clean it, or replace it.
 
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