It is likely a broken centrifugal clutch spring. It is located where the shaft meets the motor. If you are not familiar with replacing clutches, it would bebest to take it to a dealer.

Good luck
de

 

The vibration could be caused by a few things, a broken head, bad bearings in the gear head, bad bearings in the clutch cup.
You did not mention if this is a straight shaft or flex (curve) Flex shafts will fail and cause this as well, heating up and melting the plastic liner in the tube. You will need to replace the complete tube, shaft, liner and the tube it's self.

 

It is likely a broken centrifugal clutch spring. It is located where the shaft meets the motor. If you are not familiar with replacing clutches, it would bebest to take it to a dealer.

Good luck
de

Obviosly this is my first season, so these questions may seem silly but what is a ballpark figure on what this would cost at a dealer?

 

The vibration could be caused by a few things, a broken head, bad bearings in the gear head, bad bearings in the clutch cup.
You did not mention if this is a straight shaft or flex (curve) Flex shafts will fail and cause this as well, heating up and melting the plastic liner in the tube. You will need to replace the complete tube, shaft, liner and the tube it's self.

Sorry, this is a straight shaft trimmer.

 

By chance did you just change out an old head and put on a new one? If you loosen the 2 screws that hold the shaft into the nose cone pull the tube out a couple of inches to disconnect the driveshaft from the clutch and see if it turns freely, if it does, the plastic or teflon insert that holds the driveshaft is worn out , but if there is a bind when you try to turn the head by hand, take the head off and spin the gear that attaches to the head, if it is worn out, their about $85, so try and find a junk FS70,80 whatever is the same shaft as what you have, cause new parts ain't cheap. Good Luck You can do this, C'ya K

 

By chance did you just change out an old head and put on a new one? If you loosen the 2 screws that hold the shaft into the nose cone pull the tube out a couple of inches to disconnect the driveshaft from the clutch and see if it turns freely, if it does, the plastic or teflon insert that holds the driveshaft is worn out , but if there is a bind when you try to turn the head by hand, take the head off and spin the gear that attaches to the head, if it is worn out, their about $85, so try and find a junk FS70,80 whatever is the same shaft as what you have, cause new parts ain't cheap. Good Luck You can do this, C'ya K

Thanks, definitely gonna try this. You think it's covered in the warranty? Trimmer is only three months old.

 

Thanks, definitely gonna try this. You think it's covered in the warranty? Trimmer is only three months old.

I wouldn't walk into the dealersip with the attitude that it is,
instead I would let them make that decision but I also think you might get lucky there.

 

If the machine is that new, take it back,(with an open mind), let them run it, as long as you did'nt modify or change anything on the unit,(such as taking the guard of the head to let the string get long, see what they say, their going to try and find every excuse to eliminate you from warranty coverage, so make sure the machine is clean the cutter head shield is in place, the spark arrestor screen is back in place, make it look like brand new. I know you probably don't have a backup unit, but their going to give you the 'ol (We'll get to it in a reasonable amount of time"). Ask about a loaner, (If you don't ask, you don't know), if they refuse, ask for a new unit, cause that's what you walked in and payed for, if they still want to be a dick about it, search on here for a Stihl phone number and contact Stihl. Good Luck, and keep us posted, please. C'ya K

 

Just got back in town. I am taking the trimmmer to the dealer tomorrow so we'll see what happens. Thanks for the help guys.

 

if they refuse, ask for a new unit, cause that's what you walked in and payed for,

I hope you buy your equipment at Wal-Mart.

 

had the same thing happen to echo trimmer i removed drive cable, lubed, and shot grease into shaft. no more heating of shaft, vibration or noise.