Bad bearing on Stihl 461 Chainsaw?

[sc0ff]

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:

 

[pioneerguy600]

When the magnets in the flywheel pass the module /coil it will cause a jerk like that.

 

[sc0ff]

When the magnets in the flywheel pass the module /coil it will cause a jerk like that.

It feels like a magnet, but could also be thr balls in the bearings. Every video i see on youtube of people turning theirs are smooth but maybe I should take off the flywheel. I didn't know there were magnets anywhere.

 

[ZeroJunk]

Easier to take off the ignition module.

 

[sc0ff]

Easier to take off the ignition module.

I just took the ignition coil out of the way. The feeling is still there so I’m assuming the bottom end bearing are toast. I saw a guy replacing the bearings. 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 ?

 

[guysmiley]

I just took the ignition coil out of the way. The feeling is still there so I’m assuming the bottom end bearing are toast. I saw a guy replacing the bearings. 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 ?

Get a pack of small and large sandwich bags. Tag and bag.... If the project will sit longer than you can remember where stuff goes than it helps to number the bags in order of removal. Take pictures along the way as well. Good luck!

 

[guysmiley]

Also, if you don't already have one you will need a bearing puller and then some means of installing the new ones without wrecking them. Lots of ways to do it right, lots of ways to do it wrong. Plenty of videos out there.

 

[muddy42]

I have bitter experience with replacing bearings. From youtube there are various ways to remove them, as long as you don't mark or damage the case, its easy enough for a DIY-er to do. However I found reinstalling new bearings takes a level of skill that is only obtained with experience and repetition. Its so easy to fold over the inner lips, seat the bearing unevenly or end up still with an air leak. You can waste a lot of time, money and frustration with repeated attempts and damaged seals.

I will attempt pretty much any other chainsaw repair, test compression, pressure and vac test, top end rebuilds etc. But I draw the line now at cracking cases and replacing bearings. Once I have found the problem, I get someone else to do these now.

 

[Sidecarflip]

One thing about YT video's, most are loaded with false facts. I watch them for 99% entertainment and 1% factual content.

 

[altatim]

Is it an arctic model of saw? There is a magnetic coil behind the flywheel that makes it feel like it has 8 (i think its 8 magnets) specific locations that it wants to sit.

 

[sc0ff]

Is it an arctic model of saw? There is a magnetic coil behind the flywheel that makes it feel like it has 8 (i think its 8 magnets) specific locations that it wants to sit.

I’m not sure if it’s an arctic model or not. It does have a heated handle.

 

[alexcagle]

Is it an arctic model of saw? There is a magnetic coil behind the flywheel that makes it feel like it has 8 (i think its 8 magnets) specific locations that it wants to sit.

That's what I was thinking. There's a small generator behind the flywheel. Could be a handle heater power source. I don't think they put M-tronic on the 461, but I'm not for certain.
Bad crank bearings usually have up/down play, a bad seal, or metal shavings in the crankcase.
What's the cylinder walls look like?

 

[altatim]

I’m not sure if it’s an arctic model or not. It does have a heated handle.

Its probably the heated handle generator. I have a saw with the same feature but the handle had been replaced so I was unaware of the generator. I also scratched my head for a minute or two before pulling the flywheel and suddenly the 'notchy' feeling bearings felt perfect

 

[sc0ff]

Its probably the heated handle generator. I have a saw with the same feature but the handle had been replaced so I was unaware of the generator. I also scratched my head for a minute or two before pulling the flywheel and suddenly the 'notchy' feeling bearings felt perfect

How did it feel perfect without the notchy feeling? Did you remove something like the generator? The videos I see with them doing a bottom rebuild just has the floppy crank shaft when they spin it to test the fit. What's the best way to test the bearing without taking the whole thing apart? Remove the heated handle generator? I've already removed the ignition coil, did not remove the flywheel yet. Maybe I should test for an air leak with pushing air in the cylinder and squirting with soapy water around the bearings ? Last night I put the saw back together with the original cylinder and put the new kit back in the box for now. I should have taken a video of the inside but I didn't.

 

[altatim]

If you suspect that you need seals or bearings you need to remove the flywheel anyways. The generator will be behind it and has three small brass flathead screws. Make sure you don't strip them as they are quite soft. Once the flywheel was off it spun freely but I needed it off the change crank seals. I would suspect that if the scoring was from lean failure and not crank failure then you probably won't see any excessive wear in the piston skirt or lower cylinder. Check for up/down play and if it seems ok you are probably fine.

 

[stihltech]

So nobody noticed the switch on the tank for the heated handle? Yes, you need to remove the flywheel and check the bearings. No play up and down or in and out. With the flywheel, cylinder and piston of, the crank should spin with little resistance.
If it needs a piston, look the crank over REALLY well. Don't forget up and down play in the rod bearings-both ends. You will have sideways play.
AND (broken record) you WILL do a vacuum and pressure test upon reassembly. I take it you have it apart. If not do one before disassembly.
Look at all rubber parts. If questionable, replace them. I myself replace fuel and pulse hoses, plus seals on almost every rebuild.
Get a good look at the carburetor. Rebuild or replace if questionable. No, they cannot all be saved.
Ans don't forget the plug wire. No wear spots. Arcing where you can't see it has caused many a headache.

 

[alexcagle]

So nobody noticed the switch on the tank for the heated handle? Yes, you need to remove the flywheel and check the bearings. No play up and down or in and out. With the flywheel, cylinder and piston of, the crank should spin with little resistance.
If it needs a piston, look the crank over REALLY well. Don't forget up and down play in the rod bearings-both ends. You will have sideways play.
AND (broken record) you WILL do a vacuum and pressure test upon reassembly. I take it you have it apart. If not do one before disassembly.
Look at all rubber parts. If questionable, replace them. I myself replace fuel and pulse hoses, plus seals on almost every rebuild.
Get a good look at the carburetor. Rebuild or replace if questionable. No, they cannot all be saved.
Ans don't forget the plug wire. No wear spots. Arcing where you can't see it has caused many a headache.

Plus 1

 

[ZeroJunk]

We need heated handles here about as much as snow shoes.

 

[stihltech]

And I could use both in a few months.

 

[ZeroJunk]

And I could use both in a few months.

I Have never even seen a heated handle saw. Matter of fact, I have never seen when you were not taking layers off after starting on a job.