Stihl polesaw...BAD vibrations

[Bermie]

I've got a friend's polesaw...he told me its not working right and I could borrow it if I had a go at fixing it

Upon starting (starts and idles and runs fine) and after a little warm up, when I give it the gas it has a dreadful rumbling vibration in the shaft that takes a few seconds to even out...I know these polesaws to vibrate a bit on rev up but this is way beyond normal.

I gave it a basic service, and upon inspection the bar has a bit of a bend in it, not much but I can see it when I squint down the bar...

I tried running it with the bar and chain off, it seems marginally better...

He did swap heads on it, the present head unit is fairly new, I took it off and checked the gears and grease, seemed ok...

Is there any kind of support bearing within the shaft that might have disintegrated or be missing???

any other suggestions??? Ta!!

 

[John464]

there are three or four inner bearings inside the shaft that wear out. one will usually wear quicker than the others, middle bearing. I suggest replacing them all. I can tell you that putting the shaft assembly back together will try your patience. You could also have a bent inner shaft gear and in that case the shaft kit is sold as a kit not individually and costs more than half the price of a new polesaw.

 

[Bermie]

Hmmm...kinda what i thought, this polesaw has been used, and abused a lot, wouldn't surprise me about the bearings.

Is there any way to visual the bearings without a complete disassembly?

 

[John464]

Hmmm...kinda what i thought, this polesaw has been used, and abused a lot, wouldn't surprise me about the bearings.

Is there any way to visual the bearings without a complete disassembly?

you should be able to feel and hear the bad bearing. thats the only way to diagnose w/o disassemble.

watch the springs shoot out at ya. they are long, one popped me in the saftey glasses good. I wouldnt recommend taking it apart unless you have atleast 4-5hrs set aside of utter patience. good luck

 

[Rleonard]

I learned an expensive lesson with my pole saw. I had a friend "helping" me who, thru carelessness, bent my Stihl Polesaw.

It was about a $350 repair as I recall. It's been a couple of years. I had to eat the repair cost.

Now. NO ONE TOUCHES THE POLESAW other than me.

Bob

 

[Bermie]

Well, I switched the power unit and cutting head over to another pole he had, and it runs MUCH better than the old one, no where near as much vibration, so I guess its safe to say the other one is no more good...there were bits of plastic down at the power unit end when I took it apart...not a good sign! I'm not about to go as far as disassembling it to look for the bearings...our swap deal doesn't go that far!

 

[lcso10]

If you do decide to tear it down, extend the shaft all the way out so when you take it apart the springs do not have as much tension. Tear it apart and lay it out in order. After you find the problems you can assemble in reverse order.

 

[Paul001]

As already stated, likely bad bearings or bent inner shaft. If you haven't done them before, better part of the afternoon (grab some cold beers and cooler).

The resplacement shaft assemble is ~$350, comes complete and assembled.

Just to keep you awake tonight...

I'd also suggest you have the service manual handy, make up a jig to hold the shaft, a buddy around to lend a hand, and perhaps some soothing music!

Don't worry after doing 20 or 30 of them, they'll get to be just a PITA and only take up half the morning

 

[Bermie]

Thanks guys!

Darn...I shoulda put the shaft in the boat this evening, its going to be windy tomorrow and I have two saws to work on at the home workshop...dingle brain that I am I left the polesaw shaft in the truck! Mind you I don't have any beer in the fridge...got a half bottle of rum though...

 

[JohnnyBoy1986]

common issue, more than likely the inner drive shaft. they are aluminum (for light weight) and bend very easily. We're not a Stihl dealer but I guarantee i put in 30+ every year due to carelessness, snatching, tugging and swinging when they get em pinched! that whole assembly is the best solution if you dont mind spending the money.