Stihl MS 291 burnt out after 1 hr
- Thread starter west041
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I agree, but I still consider it a poor design choice. Compare to a PP5020, which has a plastic chassis but an outboard clutch and a metal cover - you will have considerably more time before case damage results. Even an outboard clutch and plastic cover will result mostly in clutch cover damage, and the outboard clutch probably can dissipate heat a bit better.
I know people like the inboard clutch feature, but I think that is a practical limitation of the material.
Even if the chain was still moving, what do you suppose caused the heating? There are two choices:
1. Clutch shoes dragging
2. Brake band dragging on the clutch
Neither of these things should happen with a brand new saw under proper operation. The saw was buried in a spruce, but it was a limbed up 14-16" trunk that was in a good spot. The saw started to smoke, at which point I shut it down. There was nothing in the chain movement to suggest slippage, brake engagement or any obstruction or clogging in the sprocket area. It wasn't like I had it pinched in the middle of a 30" weeping willow in August with a dull chain. I feel like that is what many think I was doing.
Basically the people in the "operator error" camp are saying that either:
A. I'm a liar
B. I'm incompetent
C. It was weak to begin with and you did not notice it was on until there was smoke?
Again, why should any aspect of the saw's operation be "weak" after <1 hr run time?
I see what you are saying. Who knows if they were not there. But I got to tell you it would appear the brake was left on. What would you say if for instance you loaned out a saw and it came back like that?
watsonr
Addicted to ArboristSite
A brand new saw, it should run perfect, wouldn't suspect anything else except a malfunction... something to consider. Just dogging the saw in can cause the clutch to slip and over a minute or two cause smoke to appear. A small amount of smoke wouldn't bother me, its exhaust, then holy hell, saws on fire..... I've cut a lot of wood and smoked a lot of clutches. Metal saws don't melt, but I've seen the old man light a smoke from a hot clutch and any old school logger will tell you... always carry a spare clutch with you. 14-16" wood doesn't seem like much, but dogging in can cause clutch slippage on just about any smaller saw. With the tollerance 's of today's saws and plastic parts/pieces, that heat is transferred to the plastic pretty fast. A slipping clutch builds a lot of heat, closed off by plastic... you get a heck of a mess fast. Chain moves easily after it was shut down, no brake left on...
Just thinking.
Just thinking.
Could be huh.
This is just a thought. Is it possible that the crank bearing on the clutch side could have been defective? I've installed cheap bearings on equipment that get hot and burn up quick. Learned my lesson with cheap bearings.
watsonr
Addicted to ArboristSite
yep... we all know a small saw needs a little lift on bigger wood.
Without the saw in hand, that is impossible to surmise. However, a bad crank bearing will not heat up a clutch or drum like this one was. Not that I've seen anyway. I think watsonr is on to something on this. I'm working on a video right now to show how short of time it takes to overheat a clutch on one of my rental 271's. Remember ANY time the saw is bogging and not cutting the clutch is going to get hot. This includes gunk buildup, wood beyond the capability of the saw, lack of bar lubrication, dull chains, and the clutch brake being engaged.
I also will say that this saw can still be fixed for less than $100 as long as the PTO side crank bearing and seal are in good condition. They probably are since there is still a lot of insulation provided by that oil pump and worm.
I expect my small plastic homeowner saws to run a buried bar in hardwood without a lift, other than repositioning between cuts. And they do, without issue or overheating parts. Then again I let the chain determine the cutting speed, I have dogs on very few of them and my chains are sharp. There are a lot of misconceptions about how fragile a homeowner saw is.yep... we all know a small saw needs a little lift on bigger wood.
Doug, I remember you saying in a earlier post that he was looking at 100 in parts and like 15 minutes of shop time. Let's say they whack him for a hour labor, it should only be 175 dollar repair not the 541 dollars he was quoted. Something doesn't add up.
They wanted to sell him engine cases.
watsonr
Addicted to ArboristSite
A sharp chain with lowered rakers will slip the clutch a little. A duller chain and a little lift on the handle, a little more. Just about every video on you tube of someone cutting wood shows they lift the handle... just watch a few. We lift the handle subconsciously and heat the clutch. Next time someone runs a saw, touch the clutch and see if you get your finger prints back... I'd bet not.
Was the chain sharpened at any time? Do you remember it cutting a little slower before failure? The shop saw that the clutch was overheated, assumed it was your fault based on what they have seen in the past...
These non-pro saws are pretty tough, the ms 250 happens to be one of my favorites for smaller jobs, not trying to take anything away from a homeowner saw.
Was the chain sharpened at any time? Do you remember it cutting a little slower before failure? The shop saw that the clutch was overheated, assumed it was your fault based on what they have seen in the past...
These non-pro saws are pretty tough, the ms 250 happens to be one of my favorites for smaller jobs, not trying to take anything away from a homeowner saw.
Yep, they want to replace the engine case. I have sent ones out worse than those pictures show as long as the chain brake functions properly.
It is not my place to question what one dealer wants to do. It's their choice. It's also the choice of the consumer to check out another shop. I'm just saying what I have done in the past.
Take your saw to another dealer and get a second opinion, if they both are the same then if I was you I would do one of two things.
1. order the parts and get it up and running.
2. part this one out and get a MS391 or MS362
Oh how did you call with Stihl go today?
jughead500
Sasquatch
If it were me i'd bypass the dealer and get a second opinion at another.ifthat don't work contact stihl directly.do a review on the website and see if you can attach pictures.that should get a ball rolling.
jughead500
Sasquatch
I would check the crank bearings too.
