stihl forestry clearing saw

[Anonymous-0]

This is like a weedwacker with a circular saw blade sharpened like chainsaw teeth. Straps to ashoulder harness. After about 10 minutes of cutting it slows down and dies.The unit is about 8 years old but has been running well up till now. Does anyone have any ideas what could be the problem? Thank you for any clues

 

[Anonymous-0]

Loosen the gas cap some and see if helps. I see this ALOT on my saws.

 

[D beatty]

If you haven't already done it I would clean fuel tank and change fuel filter. Also take a look at air filter to see what condition its in. When it stops have you checked the spark? You maybe having a break down in ignition system when it gets hot.

 

[tiresntracks]

All the strange things that they put in gas these days may be ruining the fuel line. It may be so soft that its almost collapsed.

 

[36F30]

(quoted from post at 09:48:19 01/20/14) This is like a weedwacker with a circular saw blade sharpened like chainsaw teeth. Straps to ashoulder harness. After about 10 minutes of cutting it slows down and dies.The unit is about 8 years old but has been running well up till now. Does anyone have any ideas what could be the problem? Thank you for any clues

Had alot of the bigger Stihl brushcutters, There is a screen spark arrester in the muffler that gets plugged with carbon, remove it and they run good again. Some were replaceable, some required new mufflers if you need the spark arrester. Especially problematic if the user mixes too much oil in the gas or running cheap oil.

 

[Donald Lehman]

You say the unit is 8 years old. After eliminating possible fuel system problems, start looking for air leaks. Leaky crank seals and/or bad crank bearings would be my guess. As the motor warms up the seals start leaking. Check your crank bearings for wear also. If you have any amount of movement of the crankshaft from bearing wear, you will leak air no matter how good the seals are. The ignition could be getting ready to crap out, too. As the unit gets hot the ignition can get weaker. This would be the least likely problem, though. Usually the newer ignitions either spark or they don't. Quickest way to check for air leaks is take it to a dealer and have a leak down test performed.

 

[Tims A]

Check the carb for a very fine screen filter. Remove the bowl, its about the size of a pencil eraser pushed into a drilled port. My weed whacker had this problem and kept getting worse till it did not run at all. Cleaned the screen, good to go.
Tim