Bad bearing on Stihl 461 Chainsaw?

[scoff]

I know very little about chainsaws but I'm pretty good at fixing things by watching a video.
I won a used saw from an auction, it won't start. I dropped it off at a service center to get a tune up and get it running but they said it had bad compression and saw scoring on the piston. They said they can't start it like it was.
I took it back and ordered an aftermarket Hyway brand piston/cylinder and ring kit and have the new one in now.

I noticed the flywheel doesn't rotate fluidly. It jumps, like when you gently pull a cord to start it. Here's a video.
Is this normal? The saw looks well used and I'm wondering if they killed the lower end and the top followed.
I wiggled the shaft on the oil pump end and it doesn't seem to have play like some videos I've seen. I haven't tried an air leak test to put air in the spark plug hole because I still have it apart from putting on the new piston.

Video:

 

[Bob Hedgecutter]

Do you still have the coil fitted in the video? If not then- Yeah na- thats not normal.
I hope you did not pay too much for it on the original auction?
Good saws and fully worth repairing for your own use, but if you paid high initially and it is going to cost plenty to repair- not really a quick fix and flip deal.

What I think might have happened is high hours or bad conditions have caused a bearing cage failure- which has let the balls within the bearing move out of position- causing your point of resistance, which has in turn take out the oil seal causing an air leak and your scoring issues.

ALWAYS (if you have the tooling) pressure and vacuum test the saw before tear down. You were hoping just replace the scored top end and all be fixed and running again- which it would for a short period of time before it took the new top end out as well.

As it stands now- take the new piston off again and back in the box, the bottom end needs to be split and bearings replaced. With the crank out move the conrod bottom end as far as you can to each side and insect that bearing VERY well before proceeding any further.
If any of the cage for that bearing is missing- cut your losses now as you will need a new crank as well.

Before splitting, strip everything off the PTO side and perhaps pull the flywheel and make sure the clunkiness is still there with just a bare crank, flush the crankcase out with gas and make sure nothing is lodged in there causing your issues- if problem persists- it is the main bearings in the case- one of which is a specific (read expensive) Stihl proprietary one on the PTO side- do not cheap out on Chinky Dink offerings.

Now, how bad was the old piston and cylinder? Unless the cylinder is scored through the plating- it can be cleaned up and used again. All transfer MUST be removed, but the OEM cylinder is the best in class if it can be retained.

 

[scoff]

I just took the ignition coil out of the way to see if the bump feeling was a magnet against flywheel. The feeling is still there so I’m assuming the bottom end bearing(s) are toast. I saw a guy replacing the bearings in a stihl 461 bottom end bearing replacement video. It looks terrible. To crack the case in half you basically have to remove every single thing off the saw and remember how it all went back. Why do they make it so difficult to replace bearings ?

 

[scoff]

Do you still have the coil fitted in the video? If not then- Yeah na- thats not normal.
I hope you did not pay too much for it on the original auction?
Good saws and fully worth repairing for your own use, but if you paid high initially and it is going to cost plenty to repair- not really a quick fix and flip deal.

What I think might have happened is high hours or bad conditions have caused a bearing cage failure- which has let the balls within the bearing move out of position- causing your point of resistance, which has in turn take out the oil seal causing an air leak and your scoring issues.

ALWAYS (if you have the tooling) pressure and vacuum test the saw before tear down. You were hoping just replace the scored top end and all be fixed and running again- which it would for a short period of time before it took the new top end out as well.

As it stands now- take the new piston off again and back in the box, the bottom end needs to be split and bearings replaced. With the crank out move the conrod bottom end as far as you can to each side and insect that bearing VERY well before proceeding any further.
If any of the cage for that bearing is missing- cut your losses now as you will need a new crank as well.

Before splitting, strip everything off the PTO side and perhaps pull the flywheel and make sure the clunkiness is still there with just a bare crank, flush the crankcase out with gas and make sure nothing is lodged in there causing your issues- if problem persists- it is the main bearings in the case- one of which is a specific (read expensive) Stihl proprietary one on the PTO side- do not cheap out on Chinky Dink offerings.

Now, how bad was the old piston and cylinder? Unless the cylinder is scored through the plating- it can be cleaned up and used again. All transfer MUST be removed, but the OEM cylinder is the best in class if it can be retained.

I did unfortunately pay a lot for this. They were surprised when I went back and told them the service guys couldn’t get it running and it was damaged. I couldn’t inspect it beforehand, it was a 6 hour away located and I made a weekend trip of it so it really cost me two days of hotels and meals and gas lol. I’m a woodworker so I just wanted a nice day to cut up the odd log blank to turn on the lathe. It was a keeper. I paid $491 Canadian after taxes and seller fees.

 

[Bob Hedgecutter]

Okay- do you have any comeback through the auction site?
We do here if goods defective or not as advertised.

If you cannot return to sender and get your money back- then we can walk you through all the repairs- heck if you want I will pull a Stihl apart and do each step with you- only I dont have a 461 available- but everything is pretty much the same in pro saws as to how you go about things.

IPL's are great diagrams for showing what goes where when reassembling.

It is a major rebuild- but its not building a Space Shuttle- at the end of the day you have a really nice Pro grade saw you know you can trust.
You do not really need a lot of tooling either- cases can be split with a brass hammer, rubber mallet or seeing as how you have a lathe- wooden mallet.
With the piston off, move the con rod over to each side and check that bearing for bits missing- if the crank bearing has gone- it might help decide yes or no to proceed.

 

[scoff]

I got the flywheel off tonight, it was super stuck on, the video make it look easy. I’ll try removing the clutch tomorrow but it also seemed stuck, the nut is super low profile so easy for you wrench to slip off.

I ordered a vacuum and pressure pump off Amazon to try an air test with soapy water, coming Monday.

 

[Bob Hedgecutter]

Hang on a minute- thats a generator under the flywheel- is it an Arctic model 461?
Rotate your crank mow with the clutch and see if the ugliness is still there.

Did not realise it was an Arctic before- lots more magnets in a generator than just the outers passing the coil pick ups.

 

[Bob Hedgecutter]

You still have the cylinder off the saw Im guessing?
So you could very possibly damage things trying to wrench the clutch off without some kind of blocking under the piston and around the conrod- like the plastic block in the ring compressor sets.

 

[Bob Hedgecutter]

The clutch nut is low profile and if you are using a standard socket or ring spanner to try and grab it- look at the inside of those- the bottom is chamfered- so you are only just getting the top of the nut- they need ground to remove the chamfer- use a quality scrench- or try an open end spanner NOT an adjustable spanner.

 

[scoff]

Not sure if it’s an arctic model, the tags just say 461 but it has on and off switch on the handle for heated grips. Turning the clutch (since the flywheel isn’t there) has smoothness, just feels like ring friction in the cylinder. I guess the bad bearing bumps was the flywheel magnets over the heater.

 

[scoff]

You still have the cylinder off the saw Im guessing?
So you could very possibly damage things trying to wrench the clutch off without some kind of blocking under the piston and around the conrod- like the plastic block in the ring compressor sets.

View attachment 1899

I put the saw back together but thought I’d give it another try. Doesn’t cost anything now to take it apart and learn something. The cylinder is back on, I used nylon rope to keep it stationary in the spark plug hole when I turned the crank so the piston was well past the exhaust port.

 

[Bob Hedgecutter]

Yes- if you had mentioned heated handles from the get go it might have speeded things up no end!
We do not see a lot of heated handle saws here- does not really get cold enough.
Well thats good news- if it now rotates freely- you will see above I mentioned something about clutch and flywheel removal to be sure of gritty bearings?
Never mind- solved now, but the clutch still needs to come off to expose the seal on that side so you can do a pressure and vacuum test.

 

[scoff]

The clutch nut is low profile and if you are using a standard socket or ring spanner to try and grab it- look at the inside of those- the bottom is chamfered- so you are only just getting the top of the nut- they need ground to remove the chamfer- use a quality scrench- or try an open end spanner NOT an adjustable spanner.

I should have caught that, good tip. I have lots of wrenches I should have used first.

 

[scoff]

I got the clutch off, I’ll do the air leak test when the pump comes. The flywheel side look clean, the clutch side looks ugly. Is that normal? I wiggled the shaft and I didn’t see any side to side movement or okay in the bearing.

 

[Bob Hedgecutter]

Pretty normal filth- not an area that gets opened out and cleaned terribly often.