Saw has thrown the sprocket e-clip/washer TWICE! Why?

[madpogue]

Stihl MS-280 C-BE. It's the kind with the easy-cheesy tool-less chain tightener, and the secondary chain-brake on the throttle. Saw has a drum/clutch sprocket. Saw is aprx. 4 years old, very few (25-ish?) hours on it. A coupla years ago, while girdling, it started running/sounding funny and wouldn't hold an idle. Took off the chain cover/adjuster, and the e-clip and washer for the sprocket were GONE, and the sprocket fell off, and either I lost the needle bearing cage or it just self-destructed when the saw ran with the sprocket all akimbo.

Argle-bargle, go get the MS180, finish the job. Got the replacement parts when I got home; noticed that the washer looked a little more substantial than the original, oh that's nice, put it back together, saw ran fine, didn't give it another thought.

Until last weekend, when the EXACT same thing happened. Again, I don't know if the needle cage bearing just disintegrated, or if I lost it in the snow when I removed the sprocket. I estimate the saw was run for aprx. 5 hours between the two incidents.

In any event, I'm wondering why the same thing would happen twice in such relatively short succession. Is this a result of me running the chain too tight, or not tight enough? Something else about how I'm running the saw? It otherwise runs great, delivers oil, eats thru firewood with a yellow chain, girdles quite handily with a green chain, etc. The only thing I can think of is that the groove in the shaft that holds the e-clip has somehow been "worn", and is allowing the clip to jump out of it. Anything (short of replacing the shaft) I could do about that? Any way I could measure that?

I know it's a consumer-grade saw, but it is a Stihl, and it doesn't have a lot of hours on it.

Hm, here's a thought -- could it be the other way 'round? Maybe the bearing wears/seizes, and that causes the sprocket to push the e-clip and washer off? I do grease the bearing periodically.

 

[fearofpavement]

How's the vibration of the saw? Ever run another one just like it to compare?

I ask because the type of problem you're having sounds like an out of balance crankshaft issue. On piston aircraft engines, if the crankshaft counterbalance weights have bad bushings it will cause the alternator belts to sling off the pulleys. That will often be the only symptom and people tend to chase the wrong thing.

I don't think you could cause that by incorrectly tensioning the chain.

 

[Sagetown]

Either the e-clip got bent when you installed it, and that's easy to do, or I'm guessing their is tremendous pressure on the e-clip from the sprocket when its running. With the e-clip missing, that bearing cage will sling out when engine is running. I would suspect the sprocket housing to be warped if there is no play in the Shaft.

 

[STIHL880]

I had this happen to me with a 6 year old MS-250 i rented. When you are putting on the chain, be sure the drive teeth are ON the sprocket, and not between the sprocket and washer. Your saw will still pull the chain just fine, but it'll pop that E-clip out in a hurry. I'll grab pics sometime or another,

And yes guys, This is Zane, (Quinn's uncle) in the hospital re covering from a stoke. hopefully.

Hope i helped out any.

 

[Sagetown]

STIHL880; my Lord what else can happen to you ? Sounds like you're being tested to the extreme.
If you're in the Hospital, you must have a Lap-Top to play with. That beats staring at the walls.

 

[STIHL880]

I know, cancer, and then a stroke? Right after my divorce, i don't fully understand it...lol. Anyhoo. Yeah, my neighbor let my borrow his laptop, especially since the guy next to me is crazy, he tried to stab the doctor with his own needle, AND he's LOADED off of meth. Crazy shizz.

But Did i help any with my last post in this thread?

Not trying to hijack..

 

[Sagetown]

I know, cancer, and then a stroke? Right after my divorce, i don't fully understand it...lol. Anyhoo. Yeah, my neighbor let my borrow his laptop, especially since the guy next to me is crazy, he tried to stab the doctor with his own needle, AND he's LOADED off of meth. Crazy shizz.

But Did i help any with my last post in this thread?Not trying to hijack..

I'd say he's getting a load of possiblities to look at.

 

[madpogue]

I know, cancer, and then a stroke? Right after my divorce, i don't fully understand it...lol. Anyhoo. Yeah, my neighbor let my borrow his laptop, especially since the guy next to me is crazy, he tried to stab the doctor with his own needle, AND he's LOADED off of meth. Crazy shizz.

But Did i help any with my last post in this thread?

Not trying to hijack..

"May you live in interesting times....."
WOW. Well, thanks for replying, in the midst of ... all that.... Um, uh, how's the food?

I don't think the vibration is excessive. Haven't run it against another one, though. I wonder if I just take the sprocket off, and perhaps even the clutch, and light it off briefly and just watch it run, if I'd be able to visually detect a crankshaft imbalance.

I know I didn't jam the chain between the sprocket and the washer. Agreed, it's kinda easy to do, esp. when changing chains / bars with that "quick-adjust" cover. Pretty sure I would've noticed a bent e-clip, and it doesn't happen right away. Warped sprocket is a possibility; I think I have another sprocket around that I can try.

Oh, and sorry 'bout posting in the wrong section; thanks to whoever moved it.

 

[Fish]

Don't start the saw with the sprocket off.

Does it have a rim sprocket?

 

[tdi-rick]

I'd suggest the circlip/E clip isn't installed the right way around.

When they are stamped they have a rough face (sharp edge) and smooth (slightly rounded) face.

The smooth rounded face should be installed against the washer and sprocket with the rough/sharp edged side facing out.

Installing the other way around may result in the rough edge digging in if there's any relative movement and forcing the clip off the shaft.

 

[MCW]

I'd suggest the circlip/E clip isn't installed the right way around.

When they are stamped they have a rough face (sharp edge) and smooth (slightly rounded) face.

The smooth rounded face should be installed against the washer and sprocket with the rough/sharp edged side facing out.

Installing the other way around may result in the rough edge digging in if there's any relative movement and forcing the clip off the shaft.

Exactly right Rick.
Thats caused a number of issues but particularly on Stihls for some reason and that line has actually been used by Aussie Stihl dealers so I gather there is some truth to it.

I've also found since owning a few Stihls that they can be harder to get the clip on and off of than lets say, Huskys or Dolmars. Easy to slightly bend that clip and not notice but it's compromised straight away. Always keep some spares and I doubt the clip coming off was caused by an earlier bearing failure - more likely the bearing disintegrated after the clip came off.

 

[tdi-rick]

Haha, I started to type that Stilh's seem more prone to it than other brands Matt then deleted it.

Thought it could result in death threats, etc.

 

[o8f150]

I had this happen to me with a 6 year old MS-250 i rented. When you are putting on the chain, be sure the drive teeth are ON the sprocket, and not between the sprocket and washer. Your saw will still pull the chain just fine, but it'll pop that E-clip out in a hurry. I'll grab pics sometime or another,

And yes guys, This is Zane, (Quinn's uncle) in the hospital re covering from a stoke. hopefully.

Hope i helped out any.

sorry to steal the thread,,,but hope you are doing ok,,you will recover from it,,i did

 

[madpogue]

It's a one-piece hub sprocket. For whatever reason, evidently because of the secondary chain brake, there is no separate hub and rim sprocket available for this saw.

Wrong-way e-clip sounds like a VERY strong possibility. I had no idea they were "sided", and never paid attention to it. I would bet that, in addition to the reason cited, the face with the rounded edge could more easily "climb" out of the slot on the shaft with outward force applied to the clip. Wow, thanks for the insight; something to pay attention to in the future.

 

[mtngun]

If that model has a clutch drum that engages the oiler spring, then make sure the spring is in the notch. If not, the drum will be pushed outward and can make the e-clip come off.

 

[Grande Dog]

Howdy,
Getting the cover good an wadded up with twigs and slash will pill the clips off.
Regards
Gregg

 

[oldsaw]

I had this happen to me with a 6 year old MS-250 i rented. When you are putting on the chain, be sure the drive teeth are ON the sprocket, and not between the sprocket and washer. Your saw will still pull the chain just fine, but it'll pop that E-clip out in a hurry. I'll grab pics sometime or another,

And yes guys, This is Zane, (Quinn's uncle) in the hospital re covering from a stoke. hopefully.

Hope i helped out any.

Good Lord, man. A stroke? On top of everything else? AND a divorce? Wow, makes my problems seem small.

But, you are right, make sure the chain is mounted right, and make sure that you aren't twisting the bar in the cut, which will do it too due to side loading, and all should be fine. 880 may be completely falling apart, but he's right.

 

[Phil_C]

It's a one-piece hub sprocket. For whatever reason, evidently because of the secondary chain brake, there is no separate hub and rim sprocket available for this saw.

That's not true. I have a MS280C with the secondary chain brake with the rim sprocket. "1121 007 1037" rim sprocket kit for MS280 and MS270 all versions in 325". How do you like the secondary brake? I ended up converting mine back to standard as I did not like it at all.

Regards

Phil

 

[rob066]

I dont know if the E clip has ever been replaced before the first occurance. If so sometimes hardware store E clips are not as thick as OEM E clips. OEM clips are twice as thick as most hardware E clips. It may be loose from being to thin and flying off.

 

[madpogue]

That's not true. I have a MS280C with the secondary chain brake with the rim sprocket. "1121 007 1037" rim sprocket kit for MS280 and MS270 all versions in 325".

The C-QS models, with the secondary brake AND the no-tool chain adjust, have a different brake band, and the drum is evidently a different diameter, so it's not compatible with the above kit, according to my parts list. It takes drum sprocket that's specific to these two.

How do you like the secondary brake? I ended up converting mine back to standard as I did not like it at all.

I could take or leave it. It hasn't given me any trouble. Then again, maybe converting to the conventional brake and going to a rim sprocket might get rid of this e-clip problem too.

I dont know if the E clip has ever been replaced before the first occurance. If so sometimes hardware store E clips are not as thick as OEM E clips. OEM clips are twice as thick as most hardware E clips. It may be loose from being to thin and flying off.

It was either from the local Stihl dealer, or from Bailey's. It was def. thicker than a hardware-store e-clip.