Stihl FS240 Brush Cutter issues ??

[MSdeer]

I have a Stihl FS240 brush cutter that I use around the deer camp, mostly cutting brush and saplings with 10" carbide tipped brush blade.  Recently it has developed 2 issues: a wobble in the shaft when revved up, and when cutting larger saplings, blade stops in the wood, even though engine doesn't kill.  I'm assuming this is the clutch slipping ?  I know the clutch could account for the blade stopping, but what about the wobble ?

[lxskllr]

Bushings on the shaft, or out of balance blade is my guess.

[MSdeer]

Bushings on the shaft, or out of balance blade is my guess.

Thanks, I haven't taken one apart yet.  One bushing on each end of the shaft ?

[Tom King]

Are you using an arbor bushing in the saw blade hole?  If so, the one that comes with the blade won't work.  They aren't thick enough to stay in place under the cup shaped washer.

I used to have a hard time with that until I found out Stihl made a special, thick bushing that solves the problem.

If that is the wobble problem, post back here, and I'll find the part number.  I only found out about them by dumb luck looking for something else on ebay.

[MSdeer]

Are you using an arbor bushing in the saw blade hole?  If so, the one that comes with the blade won't work.  They aren't thick enough to stay in place under the cup shaped washer.

I used to have a hard time with that until I found out Stihl made a special, thick bushing that solves the problem.

If that is the wobble problem, post back here, and I'll find the part number.  I only found out about them by dumb luck looking for something else on ebay.

It's not that, been using the same blades for a few years, no bushing required.

[sablatnic]

Check the nut for the blade, I have seen a lose blade once. Have you had the blade off recently?

[Kawaliga]

Did you ever grease the gears in the head, there is a large nut,
remove it, buy a tube of Stihl grease, take cap of tube, and thread
the tube into the hole you took the nut / stud out of, squeeze tube slowly
while rotating the head by hand, when you feel pressure has built up
stop, unscrew grease tube and replace nut / stud in head.
But if you have wobbles you have most likely damaged the head and will
need a new one, you could have stripped the gears causing the slipping
you mention, or the clutch could also be slipping, time to investigate.
If the clutch works like a chainsaw, then there will be a bearing for the clutch
drum to run on, that bearing should have been greased too, way before two years.

[charles mann]

I would first ck out the output shaft the blade is mounted to. If it is tight, then move on to the blade and try a different or new blade. The gearhead, as others have said, might be damaged already, but it doesnt hurt to try the simple things first. Try separating the powerhead from the shaft and spin the engine up and see if the clutch activates. Once the powerhead is separate from the shaft, you can try spinning the blade and see if the drive cable from the gearhead to the powerhead turns freely or if you are getting binding in the gearhead. 


Not sure if your local stihl dealer will do it, but you can ask them for the parts and maint manuals. Maybe for the brushcutters and other weed whacking items, the maint and parts manuals are combined, but the larger saw manuals are separate. 

[MSdeer]

Thanks for the replies, I'll get it apart soon and see what I see.  I think I will look for a maintenance manual also, as suggested.  I am afraid that if I bring it to local Stihl dealer, they will charge me more than the thing is worth.  I have found that in recent years, no-one does actual "service" any more, and with ANY type of small engine, it is best just to learn to work on it myself.