# Stihl FS 76 compression spec



## chip4664 (Aug 26, 2013)

I have a late 90's FS76. I am freshening up the carb and fuel lines and will pressure test crank to make sure seals are good. Figured I'd check compression while I'm in this far to see if it needs additional work. Its getting around 120 psi. Not sure what the spec should be on this motor. 120 seems low. It was running well with the exception of a little bog right off idle. I run either the circular saw blade or grass knife on it. Only other cause for that I could think of is the clutch springs getting weak and engaging too early.


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## AVB (Aug 31, 2013)

chip4664 said:


> I have a late 90's FS76. I am freshening up the carb and fuel lines and will pressure test crank to make sure seals are good. Figured I'd check compression while I'm in this far to see if it needs additional work. Its getting around 120 psi. Not sure what the spec should be on this motor. 120 seems low. It was running well with the exception of a little bog right off idle. I run either the circular saw blade or grass knife on it. Only other cause for that I could think of is the clutch springs getting weak and engaging too early.



120 PIS is a good starting pressure. The blogging on acceleration is probably just a low speed fuel mixture setting is slightly off. Sometimes 2Cs need to run a little rich at idle so they can accelerate properly. Note not all carbs have dual mixture screws. some have only low and other have only high adjustment and there a few that don't have any adjustments other than idle speed.


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## eiklj (Nov 15, 2013)

I have an FS74, 76, etc set up as brushcutters. If yours has a solid drive shaft, there's a bit of a lag just off idle as the shaft spools up to speed.


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## TreeTangler (Dec 6, 2013)

120 psi is about what to expect on those.


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