steel FS66 slow to rev and weak to cut

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sofasurfer

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I have a Stihl FS66 with the circular saw blade. When I rev it it takes a while to rev. When I try to cut a 1 inch tree the blade barely can get into the wood and easily stops the head from turning. I tried adjusting the carb but I'm not too good at that. I turn the idle to highest rpm and back off till rpm drops a bit then back up to higher rpm. I do the same with high speed screw. When I do I am nervous because the rpms go so high it screams but I do my best up and down and then back up. doesn't seem to help with power. Are the brush cutters really just a gimmick that does not work that well or am I not adjusting it well or is my machine worn out?
I cleaned the air cleaner. I did not look at the screen in the exhaust yet. Will do that tomorrow.
 
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sofasurfer said:
I have a Stihl FS66 with the circular saw blade. When I rev it it takes a while to rev. When I try to cut a 1 inch tree the blade barely can get into the wood and easily stops the head from turning. I tried adjusting the carb but I'm not too good at that. I turn the idle to highest rpm and back off till rpm drops a bit then back up to higher rpm. I do the same with high speed screw. When I do I am nervous because the rpms go so high it screams but I do my best up and down and then back up. doesn't seem to help with power. Are the brush cutters really just a gimmick that does not work that well or am I not adjusting it well or is my machine worn out?
I cleaned the air cleaner. I did not look at the screen in the exhaust yet. Will do that tomorrow.
Click to expand...
The brush cutters aren’t a gimmick. Your trimmer needs more that a carburetor adjustment. Adjusting a carburetor correctly takes experience and practice. Take it in to the shop if you can’t figure it out.
 
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Sounds like the exhaust is plugged with carbon. Air cannot get in if exhaust cannot get out. Some have a simple spark arrestor screen that needs to be removed and cleaned while other have a wrench fit exhaust spout that has the screen made into it. The screen needs to be cleaned with a fine wire brush and some gas, then scrubbed again with soap (dawn) and water.

For severe case the muffler may have to be removed and heated up red hot with a torch to burn out excess carbon.

Excess carbon comes from a poor fuel mix or too much oil being used in the mix.
 
sgkent

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check the air filter too
 
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sofasurfer

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Exhaust screen and air filter are clear.
Finally got it working good. Put some Sea Foam in the tank and ran it for a while. After a few minutes the rpms went up enough that the head was tuning on idle. I turned the throttle screw down a bit and then turned the hi adjustment up a smidge. Now it cuts great ( using a three headed Forester blade). It'll easily cut finger size saplings and some thumb size also.
I'm impressed and happy.
Thanks.
 
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