MS661 Clutch Problem

[Cody]

Doing routine maintenance on some saws and run into trouble with the 661. Clutch drum bearing is gone, came out in one piece but was brittle enough it broke into three pieces when squeezed. The plastic cover around the clutch is melted as well. Saw is less than a year old so I'm not sure what happened. I grease all the clutch drum bearings but I really only use my saws in the winter, don't like running them at temps above 60ºF. My first thought was maybe the clutch drum bearing was crap from the get go and wore out, causing the clutch to get hot and melt that cover, clutch seems just fine BTW. After taking that cover off though there is a piece of metal that is curved on the right side and on the left end of it has a little wiggle too it. I'm willing to bet that piece has to be attached to something but I don't have any diagrams to go off of. I would prefer not taking this to a dealer but it looks like I'll need to get that clutch out of the way, I do have a Stihl piston stop but still uneasy about removing the clutch.

I have to say that I don't think I caused this. I let the saw idle in the start position for less than 30 seconds with the brake on, but it shouldn't cause this kind of heat. Chain brake operation seems to work just fine and I always roll the chain by hand after putting it back on just to be sure. I would like to think I take good care of my saws, keep them clean and always check this stuff. The clutch on my 261C is got some pretty blue colors to it but that saw seems to operate just fine as well, maybe I'm an idiot though!

Here is the 261, it's actually newer than the 661 by build date.


I could be the last to know this as well but I like how Stihl puts their colored tie straps on the right side for semi chisel chains, and the colored tie strap on the left side for chisel, actually I don't like that but just now noticed it after all these years...

 

[CR888]

l think a pic of the problem saw in question may help rather than the ms261. I hate how stihl sells you a thousand dollar saw and fits plastic needle cage bearings amoung a host of other little savings they make like cheap china fuel filters ect, you get better needle cage bearings in AM kits that are a fraction of the price . l don't think you have a big problem but you certainly need a new clutch bearing and need to work out why things are getting so hot as to melt parts. lt don't take much of a problem to cause a lot of heat on a 90cc saw.

 

[Cody]

It was getting late but seeing as how I haven't been able to get to sleep for well over a month now I might head back out there, try removing that clutch. I will clean it out and take pictures, I would really like to know what that loose piece is behind the clutch. I just hate how my two newest saws are the ones with problems. Dad's 044 probably hasn't ever had that needle bearing serviced and it was fine!!!

Edit: I can't believe this Craftsman took off that clutch, with no piston stop nonetheless!



Carnage, guess I'm looking at more than just a new bearing!



There's that squigly metal piece I was talking about, to the left.





Although I'm not happy, I'm glad I caught this.

 

[Bill Becker]

The "squigly metal piece" engages a notch in the clutch drum and spins what you are holding in your hand. This drives the oil pump. If the clutch springs are weak or the saw is idling too high then the clutch shoes will engage the drum. If the brake is on there will be friction resulting in heat. Replace the bad parts and clutch springs as well. Make sure the chain is not spinning with the saw running and brake off. Note: the bearing rollers are only functioning at idle with the drum not turning, when the clutch shoes engage the drum the bearing rollers are not spinning, the entire assembly is spinning as a unit, because of this the bearings tend to last a long time unless overheated. Also when you are done make sure its pumping oil, there is a slight chance the o rings in the oil pump may have overheated.

 

[coltont]

Lets see a picture of your bar and chain.

 

[Foragefarmer]

Don't go aftermarket on the clutch springs; OEM only, otherwise you will be doing the same repair again.

 

[redoakman]

what kinda wood have u been cutting and what dose your bar and chain look like

 

[coltont]

Did we remember to put bar oil in as well as saw gas?

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[super3]

Fast idle start position with the brake on means the clutch is slipping generating heat. If the chain would spin with the brake off the clutch is engaged. It only takes a few seconds for it to be way too hot to touch.

 

[Cody]

Lets see a picture of your bar and chain.

I run different size bars but they're all fine, as well as the chains.

Don't go aftermarket on the clutch springs; OEM only, otherwise you will be doing the same repair again.

It'll get all Stihl parts on it.

what kinda wood have u been cutting and what dose your bar and chain look like

Oak and Ash, saw has been run through downed ash maybe 3-4 times this summer but never when it was hot out.

Did we remember to put bar oil in as well as saw gas?

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Every time it's gassed up!

Fast idle start position with the brake on means the clutch is slipping generating heat. If the chain would spin with the brake off the clutch is engaged. It only takes a few seconds for it to be way too hot to touch.

You may be right but less than 20 tanks on this saw and that spring shouldn't have been loose behind the clutch, I would think it'd take more than that. I can get pictures of the clutch and the drum.

 

[blsnelling]

I don't see how this would be possible without it being run with the chain brake on.

 

[Cody]

I don't see how this would be possible without it being run with the chain brake on.

Like I said I can't vouch that the other two ran it with the chain brake on but I doubt it. I start it with the chain brake on and release it after 5 seconds or so, just until I know the saw is going to run, I hate letting the chain spin but looks like I'll change my ways. I'm still not seeing where that spring/clip should have been loose behind the clutch.

 

[coltont]

What about sawdust clogged in the bar rail and the saw was run wide open and drug on a piece of wood till the chain spun free. But you kept trying and forgot that dragging the nose of the bar across the log to free your chain and engaged the chainbrake on assident? It happens

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[Cody]

What about sawdust clogged in the bar rail and the saw was run wide open and drug on a piece of wood till the chain spun free. But you kept trying and forgot that dragging the nose of the bar across the log to free your chain and engaged the chainbrake on assident? It happens

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I could see that situation with the 261, but the 661 requires just a blip of the throttle to clean any sawdust packed in the rails out. In fact I did it yesterday when I made 5 or so cuts, it's quite fun actually. I think I'll replace all the parts, on the 261 as well but I can't believe how blue that clutch is on that little saw, it ain't got no torque like that 661 does! No more chain brake on startups I guess, I like to be safe but screw it. I think the clutches on both saws are fine, the chain stops the saw bogs down, but they can be backups I guess

 

[super3]

You may be right but less than 20 tanks on this saw and that spring shouldn't have been loose behind the clutch, I would think it'd take more than that. I can get pictures of the clutch and the drum.

Look at the color of the clutch and drum.
It got that way from either extended fast idle with the brake on or stalling the chain in the cut and not backing off the throttle or a combination of both.

The oil pump worm gear is plastic and from the looks of the clutch and drum it was plenty hot enough to melt the worm gear enough to knock the drive tang off of it.
1 tank or 1000 doesn't have much to do with it.

 

[Cody]

Look at the color of the clutch and drum.
It got that way from either extended fast idle with the brake on or stalling the chain in the cut and not backing off the throttle or a combination of both.

The oil pump worm gear is plastic and from the looks of the clutch and drum it was plenty hot enough to melt the worm gear enough to knock the drive tang off of it.
1 tank or 1000 doesn't have much to do with it.

Beginning to realize that, just glad I caught it when I did. Here I thought buying new saws was gonna mean I didn't have to do **** to em, sometimes it's fun being stupid. Thanks guys.

 

[jr27236]

Beginning to realize that, just glad I caught it when I did. Here I thought buying new saws was gonna mean I didn't have to do **** to em, sometimes it's fun being stupid. Thanks guys.

I cant even comment to that last statement.

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[Cody]

I cant even comment to that last statement.

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Sure ya can!

 

[jr27236]

Sure ya can!

I just never found it fun when I did something stupid, it either cost me money or hurt lol

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[banana boat]

"I hate letting the chain spin but looks like I'll change my ways"

You idle should be set so the chain does not spin while the saw is idling with the chain brake off, otherwise when you have the chain brake on you will be overheating your clutch....