Stihl Farm Boss MS271 just stopped

ikeepgrnbarsfull

New Member
May 14, 2020
10
Frederick, MD
Literally. It has been running perfectly fine. It was running perfectly fine. I finished my cut and it just turned off, no coughing, no bogging, no sputtering; it went from full throttle to off. When I tried to restart it, I got nothing. Again, literally nothing, no cough, sputter, smoke, just nada.

Now the things I know I've done wrong :(
It's four years old and I've never done a tune up. But I've also ran less than two gallons of gas through it.
Which has already set off alarm bells in many of your heads and you're right: I'm that new guy who stored it with gas in the tank.
And you're right again, I'm using old, but stabilized gas.

May or may not be related:
I just changed the chain because I didn't feel like sharpening the one that was on it. I had a VERY dangerous ADD moment and forgot to tighten the bar nuts. Believe me when I say I'll never run a saw again without my meds. After a few attempts at trying to start it I noticed I was missing a nut and the second one was loose but the bar still seemed snug enough. Unsure when that nut came off.
Been running 0w20 or 0w40 Mobile One as bar oil... I was under the impression it just means I go through it faster because it's thinner and isn't "sticky".

Things I checked:
Seems to have compression, and guy at dealer confirmed that
Is not seized, I assume I couldn't pull it if it were and guy at dealer confirmed that it's not.
Chain tension seemed fine, bottom pulled down the right amount, and dealer guy confirmed that

Dealer guy said 1-2 weeks before they could look at it but I want my saw now because it's a great source of exercise and stress relief haha. I'm fairly mechanically inclined and have done a lot of work on cars and golf carts with little more guidance than what I've pulled from Google, forums, and YouTube. But...when I googled my problem all I got was a thread on here about a guy with a seized Stihl and that wasn't much help (though it did say something about redoing the cylinder with an aftermarket kit and getting more power out of it. And that did interest me. Are there aftermarket upgrades for these saws?).

In my head it seems like a fuel or spark issue with either the fuel line being completely occluded or the plug being totally dead. Anyone have any thoughts? Any information I've left out? Any good source for a tune-up/maintenance kit and how to or should I just grab it from the dealer and try it instead of waiting two weeks?

tl;dr
Four year old chainsaw with old gas and no tune up go brrrrrt always, then no more brrrrt suddenly. Chuck go wtfmate ¯\_(ツ)_/¯
 

GadDummit

Burning Hunk
May 27, 2017
195
Oklahoma
Haha, love the tldr. Check to see if the gas line is clogged inside, and the air filter. Either one can kill your sawing right dang now. Fuel line might be broken too, that happens. Just open it up and look inside. You should see if there's muck or a broken line pretty easy. Change out the gas too just so you have as much pow as possible while you troubleshoot.
 

brenndatomu

Minister of Fire
Aug 21, 2013
4,998
NE Ohio
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DodgyNomad

Minister of Fire
Dec 19, 2009
539
West Michigan

jeffoc

Member
Oct 3, 2008
122
Blandinsville, IL
I had a fuel line go on mine before. You probably would have noticed the smell, but it's an easy check.
 

brenndatomu

Minister of Fire
Aug 21, 2013
4,998
NE Ohio
it's likely the coil on that model.
Yup, my 290 would run for a few minutes and then just shut off like you hit the kill switch...would run for a bit again the next day...needed a coil.
 

salecker

Minister of Fire
Aug 22, 2010
1,066
Northern Canada
Check for spark
Check for gas, if spark is there try a little gas in the carb,if nothing...
Pull the muffler and look at the piston through the exhaust port.
 

Jags

Moderate Moderator
Staff member
Aug 2, 2006
18,122
Northern IL
Keep in mind that it isn't unusual for a bad coil to work when cold but fail as it warms up.
 
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JRHAWK9

Minister of Fire
Jan 8, 2014
1,427
Wisconsin Dells, WI
Keep in mind that it isn't unusual for a bad coil to work when cold but fail as it warms up.
Similar to the old Ford ignition module boxes of years ago. :) Remember friends holding bags of ice over them to cool them off so they could make it home. ;lol
 

brenndatomu

Minister of Fire
Aug 21, 2013
4,998
NE Ohio
Similar to the old Ford ignition module boxes of years ago. :) Remember friends holding bags of ice over them to cool them off so they could make it home. ;lol
They make freeze spray in aerosol cans specifically for diagnosing intermittent electronic issues like that...works great...sometimes... ;lol
 
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kennyp2339

Minister of Fire
Feb 16, 2014
4,897
07462
Check and make sure the wires going to the kill switch are still connected, something could have vibrated off, then check for spark, clogged air filter, dirty spark plug, also when you say stabilized fuel, mix fuel right?
 

maple1

Minister of Fire
Sep 15, 2011
10,462
Nova Scotia
Sounds like a spark issue to me, if it was working as it should have before it quit.

First thing for me would be to put a new plug in & try it. Go from there.
 

Sodbuster

Minister of Fire
Sep 22, 2012
1,454
Michigan
Blah, blah,blah, all I can do is parrot what others have said, sounds electrical, check for spark, and report back.
 

ikeepgrnbarsfull

New Member
May 14, 2020
10
Frederick, MD
Update:
Dealership just called. Said my cylinder and piston are toast and would cost me about $350 after labor to repair. Looking at my 50:1 labeled gas can I'm starting to think I might/probably/almost definitely filled it to the 2.5gal mark. So chalk one up to unmedicated ADHD, remember: May is Mental Health Awareness month.

So does anyone know if scored cylinders can be salvaged and maybe then I'll just need a piston?

In the meantime, I think I'm going to get an MS261 and not be an idiot

Tl;dr
ADD + gas mix = 62.5:1 not 50:1, scored cylinder and piston. Toss a coin to your witcher.
 

brenndatomu

Minister of Fire
Aug 21, 2013
4,998
NE Ohio
Update:
Dealership just called. Said my cylinder and piston are toast and would cost me about $350 after labor to repair. Looking at my 50:1 labeled gas can I'm starting to think I might/probably/almost definitely filled it to the 2.5gal mark. So chalk one up to unmedicated ADHD, remember: May is Mental Health Awareness month.

So does anyone know if scored cylinders can be salvaged and maybe then I'll just need a piston?

In the meantime, I think I'm going to get an MS261 and not be an idiot

Tl;dr
ADD + gas mix = 62.5:1 not 50:1, scored cylinder and piston. Toss a coin to your witcher.
If the cylinder just has aluminum smeared on it, then yes, it can be salvaged as long as there is no other damage.
I won't run 50:1 on my stuff, even with oil that says it can be...that is VERY little oil lubricating your engine at 13,000 (+) RPM...and NO margine for error as you found out.
 

jeffoc

Member
Oct 3, 2008
122
Blandinsville, IL
If the cylinder just has aluminum smeared on it, then yes, it can be salvaged as long as there is no other damage.
I won't run 50:1 on my stuff, even with oil that says it can be...that is VERY little oil lubricating your engine at 13,000 (+) RPM...and NO margine for error as you found out.
Just curious, What ratio do you run. I just bought a Husky 550 MK2 waiting for it to be delivered and want to have it around for a while.
 

Sodbuster

Minister of Fire
Sep 22, 2012
1,454
Michigan
Update:
Dealership just called. Said my cylinder and piston are toast and would cost me about $350 after labor to repair. Looking at my 50:1 labeled gas can I'm starting to think I might/probably/almost definitely filled it to the 2.5gal mark. So chalk one up to unmedicated ADHD, remember: May is Mental Health Awareness month.

So does anyone know if scored cylinders can be salvaged and maybe then I'll just need a piston?

In the meantime, I think I'm going to get an MS261 and not be an idiot

Tl;dr
ADD + gas mix = 62.5:1 not 50:1, scored cylinder and piston. Toss a coin to your witcher.
Do they make an oversize piston for that engine, or even oversize rings? A machinist could hone or bore it out for you. Running richer than 50:1 isn't necessary. I have a Husqvarna 45 circa 1995 that has cut countless cords of wood, all on 50:1, and oils have come a long way since then. I use Stihl Ultra synthetic in the silver bottle and non ethanol 90 octane fuel in all my 2 stroke stuff.
 
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brenndatomu

Minister of Fire
Aug 21, 2013
4,998
NE Ohio
Just curious, What ratio do you run. I just bought a Husky 550 MK2 waiting for it to be delivered and want to have it around for a while.
32:1 usually...I'll go to 40:1 with full synthetic.
 
Last edited:
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salecker

Minister of Fire
Aug 22, 2010
1,066
Northern Canada
Do they make an oversize piston for that engine, or even oversize rings? A machinist could hone or bore it out for you. Running richer than 50:1 isn't necessary. I have a Husqvarna 45 circa 1995 that has cut countless cords of wood, all on 50:1, and oils have come a long way since then. I use Stihl Ultra synthetic in the silver bottle and non ethanol 90 octane fuel in all my 2 stroke stuff.
No such thing as overboring a chainsaw cylinder anymore.
95% of cylinders with aluminum transfer can be cleaned and reused.
50:1 mix is like playing russian roulet,it will cost you at some point.But it is your saw so run what you want in it.Saw builders/porters who stand 100% behind thier work will tell you 50:1 is trouble waiting to happen,so your choice.
 

salecker

Minister of Fire
Aug 22, 2010
1,066
Northern Canada
Update:
Dealership just called. Said my cylinder and piston are toast and would cost me about $350 after labor to repair. Looking at my 50:1 labeled gas can I'm starting to think I might/probably/almost definitely filled it to the 2.5gal mark. So chalk one up to unmedicated ADHD, remember: May is Mental Health Awareness month.

So does anyone know if scored cylinders can be salvaged and maybe then I'll just need a piston?

In the meantime, I think I'm going to get an MS261 and not be an idiot

Tl;dr
ADD + gas mix = 62.5:1 not 50:1, scored cylinder and piston. Toss a coin to your witcher.
If you are mechanically inclined you can fix it yourself.
Fun project,sense of accomplishment,and save some money.
 

brenndatomu

Minister of Fire
Aug 21, 2013
4,998
NE Ohio
I use 40 to 1 in summer the smoke keeps the skidders away
What oil are you running? Should be no perceivable smoke at 40:1...heck, I don't get smoke at 32:1 except on cold start up when using the choke.
 

Sodbuster

Minister of Fire
Sep 22, 2012
1,454
Michigan
Just curious, What ratio do you run. I just bought a Husky 550 MK2 waiting for it to be delivered and want to have it around for a while.
Run what the manufacturer calls for any high quality 2 stroke oil will do, Stihl, Husqvarna etc. Don't cheap out on oil.
No such thing as overboring a chainsaw cylinder anymore.
95% of cylinders with aluminum transfer can be cleaned and reused.
50:1 mix is like playing russian roulet,it will cost you at some point.But it is your saw so run what you want in it.Saw builders/porters who stand 100% behind thier work will tell you 50:1 is trouble waiting to happen,so your choice.
OK, I'm always willing to be educated, I have no doubt the 50:1 ratio came straight from the EPA. I bought a Stihl MS 261, it's not even broke in yet. It was a lot of money for me, but I wanted a good saw, that I wasn't constantly wrenching on vs cutting. How rich do saw porters recommend? Math is not my strong suit so how much fuel to add to a 2.6 oz bottle of oil?