still ms250 question

[tobers]

my friend had a new ms250. He isn't exactly mechanically inclined and he burned it up about the 3rd time he used. He isn't sure what happened, but the shop says that he ran it full throttle with the brake on. Anyway, the shop wouldn't fix it so my friend threw the new saw in the trash. I got it. Just took it apart. From the pic you can see that the case took some intense heat around the clutch. I was going to put a new clutch in it, and new bearings. I think everything else is good. I don't see anything else bad. Here is my question: behind the clutch, in the plastic housing, are little reservoirs, or voids. Are those just for strength? Or do they have some other function? In other words: can I use this old case, as fried as it is, or do I need another plastic case? thanks! rick

 

[HarleyT]

You can reuse all of the parts, more than likely. The danger about the melting on the case would be the passages within the crankcase that carries the bar oil, and/or the plastic that holds the oil pump in place. See if the chain brake still works, release it, and put the saw back together, and see what it does. Run it with the bar and chain off, to view the oiling, etc. See if it runs OK. Idles, etc.

 

[HarleyT]

That saw doesn't look too bad, you might have to shave off some molten plastic.

 

[tobers]

I know the brake "clicked" into both positions because when I was disassembling the saw, I did that by mistake. I didn't check to see if it braked like it should.

I can feel one bearing is rough, so I'll replace both of those.

I looked at the oil pump. See pic. I think there is a thin bit of melted plastic one side of it. I'm pretty new at this ... wha does that metal curved piece ride in/attach to? If its the casing, that might be a problem.

 

[HarleyT]

The curly spring sticking out fits in the notch in your sprocket/drum, and it turns the oil pump.
So if the chain is not moving, it won't pump oil.

 

[HarleyT]

Here is the mech manual. The 025 and the ms250 are the same saw.

 

[tobers]

I found a video. I found out how the oil pump works. I'll get bearings. And maybe a clutch kit that will have the new piece above. And then do what you suggested to test for idle and oil. Any suggested place to get bearings and a clutch kit? thanks again. Rick

 

[HarleyT]

E-Bay.

Just get an OEM clutch for the ms170, same one.

 

[HarleyT]

@ $20 for a new oem.

 

[Chris-PA]

These melted Stihl threads are getting to be like oil threads.

 

[hotshot]

Yep, but don’t be a Stihl hater as there’s thousands of those saws sold annually, and quite a few folks that cut wood & drive with the brakes on.

 

[Khntr85]

Any saw ran with brake on will burn up, regardless of brand good lord!!!

 

[LoveStihlQuality]

I know the brake "clicked" into both positions because when I was disassembling the saw, I did that by mistake. I didn't check to see if it braked like it should.

I can feel one bearing is rough, so I'll replace both of those.

I looked at the oil pump. See pic. I think there is a thin bit of melted plastic one side of it. I'm pretty new at this ... wha does View attachment 625875 that metal curved piece ride in/attach to? If its the casing, that might be a problem.

Worm gear.

Couple summers ago, walking dog, ran across two brain trusts trying to cut up little tree but chain wouldn't turn. Flip flops shorts. Showed them chain brake. Went home by different route so that I couldn't see what body parts were cut off.

Sent from my SM-N900P using Tapatalk

 

[Chris-PA]

Any saw ran with brake on will burn up, regardless of brand good lord!!!

Maybe eventually, but there is a clear difference with these saws. An inboard clutch and a plastic case is a design that is very vulnerable to exactly what you see here. With an outboard clutch the heat source is farther from the plastic case - maybe you'll melt the clutch cover.

As a product designer, if your design is easily damaged by events that are very likely to happen, you've got a problem. It's only worse when your instructions lead people to do exactly that thing.

Anyway, the proof of the pudding is in the eating. The melted case threads are common and all of them are Stihls.

 

[1Alpha1]

I never engage the brake on my saws for any reason. Yeah, it's there for a reason, and the saw will engage it when it's appropriate.

 

[Icedogs28]

I never engage the brake on my saws for any reason. Yeah, it's there for a reason, and the saw will engage it when it's appropriate.

Same here

 

[1Alpha1]

Weird how so many seem to struggle with the brake on their saw.

Some don't seem to know if it's on or off..............

 

[Icedogs28]

Weird how so many seem to struggle with the brake on their saw.

Some don't seem to know if it's on or off..............

I see so many YouTube videos where guys start the saw, then rev it to warm it up, with the chain brake on!! Drives me nuts. I guess I should relax and just laugh..

 

[tobers]

yep. But this guy is a friend ... grew up in a big city ... and is unacquainted with chain saws, tools, and anything out of doors. So he was really excited about his saw. He even got the protective gear. He was "all in." So I was sad when this happened, as it threw water on his dream to be an outdoorsman. He felt pretty stupid. Having said that, I can understand the brake going on by mistake. What I can't imagine is trying to rev the engine higher in an attempt to cut, and not noticing it. Or throwing a new saw in the trash can.

 

[Okie]

The newby rookie dreaming about becoming an outsdoorsman should have started out getting his experience with a cheap type Crapsman saw instead of getting his wood cutting experience with a good saw. (and probably not even reading the owners manual) The Crapsman saws are designed to be trash canned if not used as OCCASIONAL USE SAWS.

Sounds like he (the Newby rookie) was out cutting by himself, he is lucky that it was the saw that got damaged and not him.