Overheating chainbrake on ms880, burned up oiler, piston ect Anyone else?

[jagchaser]

I bought a brand new ms880 this spring. I put it strictly on a 36" Alaskan mill running the 41" bar. I milled maybe 20 logs with it so far.

Saturday it starts fine and warms up for about 10 seconds and dies.

I took it to a Stihl service center today and he told me that stihl would not warranty it because he says it ran with the chain brake on. He says it melted the oiler, burned up a bearing and scored the piston. $900 or so fix it.
I have had the chain brake set when cutting, but within a split second my finger is off the throttle. I have never seen it still turn after the brake sets itself. The brake itself doesn't set very often either.

I tried to figure out how it could run with the chain brake on at all and we talked about my mill. He called me back later to say that maybe it wasn't the chain brake, but that I may have been overloading it "pushing logs thru"?? He then told me that even if I paid to have it fixed that it would probably happen again because its not meant to mill with. He said my original warranty would still be intact, but would not be extended if he fixed it, and of course it wouldn't be covered again if I overheated it milling.

I don't pressure it into the cut, but mostly let it cut its way down. I have put about 20 pounds of weights on the rail to help keep it from vibrating. It doesn't stall out or act like its overloaded at all.

Im kind of at a loss here. I ran it the same way I used to run my smaller mill and I never had problems with that. Maybe my chain brake IS the problem? Im tempted to take it off after I get the saw back from him. I cant imagine that milling is overloading it if Im not pushing mill into the cut?

 

[Jacob J.]

It sounds like your dealer isn't diagnosing the problem(s) correctly. Does your saw even have all the problems suggested by the dealer?

 

[dave53223]

I mill with a friend, We have the same setup and no problems. We have more use with a 56 inch mill than the 36 and no problems with the saw.

 

[jagchaser]

I suppose I should go take pictures of all the issues he claims are there. The only thing I ever saw was that the flywheel? seemed loose and was rubbing on the magneto? I don't know enough about them to know what the actual names of the parts are or how to tear into it to see if the oiler is melted.

I doubt he has even seen an 880 before. Im out in the middle of the plains where we don't have trees big enough to justify that saw unless you are milling.

 

[dave53223]

I cut big fire wood with the saw one time. Other that that we mill with the saw. The purpose of the big saw and a chain saw mill is to get logs you can not get any other way. We milled about twice what you did. Most of the milling is with the large mill. No problem with the saw.

 

[Gypo Logger]

Sounds like the dealer is full of it! I've heard of this sorta thing over and over again from both stihl and husky dealers. If you know more than them about saws and are a repeat customer than your ok, but if your just off the street, than watch out!

 

[nmurph]

Hypothesis: not enough oil- toasted the bearings, letting them flop around, rubbing the coil, and scoring the cylinder.

 

[AKDoug]

I agree nmurph, if the flywheel is moving around, the crank bearings are shot. Milling puts a tremendous load on saws, even though many people do it with no problems at all, a saw is not designed to mill.

 

[Big_Wood]

i have seen a dealer diagnose wrong way way to many times. i've had saws that are apparently cooked bearings and all only to tell the owner take it back anyways. they always hit you with the (leave it here and you don't have to pay your bill) BS. my brother in law had a 268 at the dealer and it apparently had cooked bottom end bearings. all that happened was it quit running. they told him leave it here and you don't have to pay your bill. i told him o go get it and every single bearing was tight, top end was minty but it wouldn't run. the only thing wrong was the kill switch wire had broke and grounded on the case. i was so ****'n difgusted and pissed off that i went and talked to that dealer with the saw in hand. i'll leave it at that.

 

[2dogs]

Contact Stihl directly.

 

[w8ye]

I run my oil at 32:1

 

[VinceGU05]

Hypothesis: not enough oil- toasted the bearings, letting them flop around, rubbing the coil, and scoring the cylinder.

yup i like this theory.! you running 50:1 ? would run at least 25:1 open up the muffler so it can run a bit cooler, and rebuild it yr self if you can. that will save you 2 to 300 bucks.

my 084 flywheel flopped around like that too but i had a busted crank. a failed bearing will simulate the same.

 

[SEAM]

Too much tension on the chain can also cause bearing trouble... not saying that's the cause, but I have seen saws like that.
The flywheel rubbing against the coil indicated bearing play/damage, not necessarily from use but possible due to a defective part when new. If the play is excessive in both bearings the clutch drum will touch the brake causing plastic parts to burn up.
You may want to try another dealer or contact Stihl directly.

 

[jagchaser]

1. I use a 6.4 oz can of stihl oil in 2 gallons of gas, so 40:1 Im surprised that the oil calls for 50:1 on the instructions.

2. Tension is a possible issue. This is my first big saw with a big bar. I have a 390 with a 24" bar and I know how to set the tension on that, but Ive never really seen how much play should be on a 41" bar. What could that have caused? Bearing going out then rubbing on the brake then overheating? Should I ask him to look at the bearings and see if defectively loose bearings could have caused the drum to touch the brake then causing the overheating?

3. I have not set up an auxillary oiler on this yet. I kind of assumed I wouldn't need it unless I went bigger than the factory bar. Could that have been part of the problem?

4. Opening up the muffler, are there aftermarket mufflers to do that or are you saying drill it out or something like that?

5. If rebuilding it myself is only going to save 2-300 then Im not going to do it. I just want to make sure it will not do this again.

 

[SEAM]

The bearing itself will stay in place, but the bearing cage (spacing the bearing balls evenly around the circumference) breaks easily under stress causing the balls to be spaced unevenly and accumulate in places, resulting in excessive play. If this happens, the crankshaft can move quite a lot up/down or forward/back. When both bearings are affected the whole crankshaft will slant a little due to the play (backward on the flywheel side, forward on the clutch side when the chain is tensioned repeatedly). The engine usually will start to draw air through the crank seals causing a too lean air/fuel mix (-> piston/cylinder scoring) and the clutch drum being pulled forward may touch the break band causing heat (friction)...
This is just an imagined scenario, but I have seen a couple of saws with that sort of damage. I also have a 038 where the previous owner dropped a number oft trees with the chain brake engaged - the pump drive gear was melted to a white coating on the drum in that one.

 

[z71mike]

4. Opening up the muffler, are there aftermarket mufflers to do that or are you saying drill it out or something like that?

No aftermarket exists that is any different than the factory setup. You're gonna hafta mod it yourself. There are alot of muffler mod threads on here. The search should show a good amount.

 

[Blanc]

Well I'm no stihl expert and hate their latest models,
But IMHO to toast a roller that fast you'd at least made the gas boil several times.
I mean I used to run pretty small saws for milling (jonsered 550 and partner 450) for both I made gas boiling, the partner's piston ring was something I changed every 100 bd meter but I never succeed burning rollers and oilers and both of them probably did one or two thousands board meters, and they are still there and running.

I think that your dealer is trying to get your money...

 

[nmurph]

The dealer has agreed to fix it under warranty.

 

[dave53223]

The dealer needs to fix the saw under warranty. Running a big mill like I do is a lot harder on the saw than you are. this saw runs perfect. All we do is clean the air filter.

 

[jagchaser]

The dealer has agreed to fix it under warranty.

Are you the guy I talked to from the distributor?

I sent an email to Stihl today and someone from the distributor called this afternoon. Explained it all again, but it looks like he had already heard my side! They agreed to take care of it, so I am still completely satisfied with Stihl! I cant wait to get back to cutting!