Stihl MS271 crushed

[Pripyat]

I've had this saw a couple years, have maybe 10 hours on it. I had a tree start falling but only tilted 10 or 15 degrees before it became entangled on those around it. Long story short I got the saw stuck while cutting through the remaining wood fibers between the notch and the back cut. No problem, I attached the tow rope to the tree and snatched it off the remaining log. I have no idea how physics managed to let this happen but the saw fell, flipped under the tree, and was.. piledriven?

I'm attempting to revive this one before I commit to getting the MS261 I've been wanting. If the engine on the damaged MS271 is repairable within reason I'll look into getting a new handle and some new plastics.

When I attempt to turn the engine over there is more resistance than there was before. Seems like it is only in one spot, aligns perfectly with the compression stroke. I stripped the powerhead down and I can tell when I slowly turn the engine over by hand that the flywheel has a high spot. In other words the distance from the engine to the edge of the flywheel varies as the engine is turned over.

How can I determine whether the flywheel is bent or if the crankshaft is bent? If it is the crank I would be tempted to bang on the high spot with a piece of wood to attempt to straighten it and get some more life out the powerhead. Depends on the cost of a crank I guess. Any input is appreciated!

 

[HarleyT]

I don't think the flywheel would bend.
The crank stub is pretty short there too.

Any pics of the saw on the bench?

 

[HarleyT]

Here is a pic of a 271 flywheel, brittle aluminum mostly...

 

[HarleyT]

Here is a side view of the crank bottom.

 

[HarleyT]

I always keep a old worn out bar and chain behind the seat, and if I get the saw snagged, I unbolt it from the pinched bar and chain, and pop on the old bar/chain to cut and free the good bar/chain. Also keeps the saw out of harm's way.

 

[grizz55chev]

I always keep a old worn out bar and chain behind the seat, and if I get the saw snagged, I unbolt it from the pinched bar and chain, and pop on the old bar/chain to cut and free the good bar/chain. Also keeps the saw out of harm's way.

I just carry 3 saws, problem solved!

 

[ThackMan]

Next time just take the bar off before pulling on the snag.


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[Pripyat]

Wow this forum is active. I love it. Hopefully you guys are as quick to respond with land management / tree planting / tree care / etc. I'm about to build a house on 43 acres of partial wetland, farmland, and hardwoods.

As far as the saw - Thanks for those pics. At a glance I can't imagine that crank bending. The flywheel is an entirely different story. I'm going to make a puller some time today and see if I can establish anything. Flywheels are cheap so I may just go ahead and get one on order. I'll post up some more pics as well.

I'm just an amateur hobbyist at best when it comes to logging. I did buy and read "to fell a tree", though. Great read.

 

[HarleyT]

Just loosen the nut, and pick up the saw by the flywheel, put a deepwell 13mm/1/2 inch socket on the nut, and smack the socket with a hammer, the flywheel will drop right off. Use an impact wrench or drill driver with impact action to loosen the nut. Just back the nut off slightly before giving it a rap.

 

[moresnow]

Interesting accident. Another one of lifes little learning experience's!
If the flywheel appeared to rotate out of round the crank may have been knocked out of phase/alignment as you have deciphered. Not so good. A shade tree fix on that may be tough!
Good advise from these guys already to prevent this from happening.
Good luck.

 

[Pripyat]

What are you guys' thoughts on straightening the bar and then filing to ensure the chain can slide freely? It looks like I can get a used crank, flywheel, and starter cover for less than the cost of a new bar/chain.

 

[user 122190]

Damn nearly impossible. To much precision an strength, to crudely bend it back. I once attempted this and gave up quickly. Maybe with a strong deck and a hydraulic press, and a lot of luck.

What are you guys' thoughts on straightening the bar and then filing to ensure the chain can slide freely? It looks like I can get a used crank, flywheel, and starter cover for less than the cost of a new bar/chain.

 

[holeycow]

you might be able to straighten that bar with a press, proper blocking, and some patience

 

[Big Red Oaks 4 me]

It could have been worse. It could have been a Husqvarna.

 

[merc_man]

Did the tree move the coil a little and rubbing on fly wheel in a sertain spot.

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[Overkill338]

Throw a popup piston meant for a 261 in it. Give it some extra pep.

 

[JTM]

The extent folks will go to get a new saw. Just show the missus the picture. She’ll let you get that new saw.

 

[Pripyat]

My wife already signed off on the MS261 purchase. My issue is that I don't throw stuff away and I don't want to have to store all these MS271 parts for the next 50 years. Not to mention next time I drop a grand at the Stihl store I would rather get a bunch of stuff I don't already have - Like more trimmer attachments.

The trick to get the flywheel off worked wonderfully. Backed off the nut a thread or so, held up saw by flywheel, smacked socket on flywheel nut with a hammer. Popped right off. I sat the flywheel on the table and it was not bent in regards to the flat base on the bottom. I got to looking where the cam mated up to the flywheel and it doesn't look good.

I had a hard time getting a decent picture but you can see an indention in the flywheel at the key slot where the cam was "pressed" into it.

That and the fact that the engine turns over relatively easily has me thinking that a new flywheel will correct the issue. I ordered a new pullcord assembly with side cover used on ebay along with a used flywheel. Both set me back around $50.

I'll know in a week where we sit. Worst case I'll have to get a camshaft I think.

 

[ThackMan]

That’s actually a “crankshaft” not a camshaft. FYI


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[Pripyat]

Those are interchangeable right?