# Stihl Farm Boss MS271  just stopped



## ikeepgrnbarsfull (May 14, 2020)

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)_/¯


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## GadDummit (May 14, 2020)

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.


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## brenndatomu (May 15, 2020)

ikeepgrnbarsfull said:


> In my head it seems like a fuel or spark issue


I'd check for spark...


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## DodgyNomad (May 15, 2020)

brenndatomu said:


> I'd check for spark...



This.   Plug, check on/off/choke lever, if still no spark, it's likely the coil on that model.


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## jeffoc (May 15, 2020)

I had a fuel line go on mine before. You probably would have noticed the smell, but it's an easy check.


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## brenndatomu (May 15, 2020)

DodgyNomad said:


> 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.


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## JRHAWK9 (May 15, 2020)

brenndatomu said:


> I'd check for spark...



My first thought was coil......


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## salecker (May 15, 2020)

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.


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## Jags (May 16, 2020)

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 (May 16, 2020)

Jags said:


> 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.


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## brenndatomu (May 16, 2020)

JRHAWK9 said:


> 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.


They make freeze spray in aerosol cans specifically for diagnosing intermittent electronic issues like that...works great...sometimes...


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## kennyp2339 (May 17, 2020)

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?


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## maple1 (May 17, 2020)

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.


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## ben94122 (May 17, 2020)

Just going back to basics, make sure you didn't run out of gas...


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## Sodbuster (May 17, 2020)

Blah, blah,blah, all I can do is parrot what others have said, sounds electrical, check for spark, and report back.


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## ikeepgrnbarsfull (May 20, 2020)

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.


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## brenndatomu (May 20, 2020)

ikeepgrnbarsfull said:


> 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?
> ...


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.


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## jeffoc (May 20, 2020)

brenndatomu said:


> 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.


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## Sodbuster (May 20, 2020)

ikeepgrnbarsfull said:


> 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?
> ...



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 (May 20, 2020)

jeffoc said:


> 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.


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## salecker (May 21, 2020)

Sodbuster said:


> 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.


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## salecker (May 21, 2020)

ikeepgrnbarsfull said:


> 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?
> ...


If you are mechanically inclined you can fix it yourself.
Fun project,sense of accomplishment,and save some money.


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## johneh (May 21, 2020)

I use 40 to 1 in summer the smoke keeps the skidders away


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## brenndatomu (May 21, 2020)

johneh said:


> 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.


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## Sodbuster (May 21, 2020)

jeffoc said:


> 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.


salecker said:


> 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?


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## johneh (May 21, 2020)

I use a 2.5 US gal gas can
witch is just short of 10 liters
I add 1 -200ml bottle of Stihl 2 cycle oil 
My oldest saw a 026 has run this since new
and it still runs like new  It is 28 years old
and cuts between 10 and 20 cord a year
It is my go-to saw out of 3 Stihl saws I own


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## Sodbuster (May 21, 2020)

That is why I only mix up a gallon at a time. My Stihl oil says to mix with 1 gallon of gasoline, easy peasy. Trying to jump between metric and oz will cause you headaches.


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## johneh (May 21, 2020)

Sodbuster said:


> That is why I only mix up a gallon at a time. My Stihl oil says to mix with 1 gallon of gasoline, easy peasy. Trying to jump between metric and oz will cause you headaches.


Not if you are a Canadian in my age group we were brought up with Metric and Imperial 
Going from one to the other is normal for anyone in a trade 
ex 60 = 15 10 = 50  0 =32  I can also do inches to cm or parts thereof
In my trades( 3) you have to know both


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## Sodbuster (May 21, 2020)

johneh said:


> Not if you are a Canadian in my age group we were brought up with Metric and Imperial
> Going from one to the other is normal for anyone in a trade
> ex 60 = 15 10 = 50  0 =32  I can also do inches to cm or parts thereof
> In my trades( 3) you have to know both



I'm not in a trade, but was educated in the 70's when the US was going to go metric, but never did, forgive me for not remember details from the 6th grade. We don't sell fuel in in the US by the liter it's by the gallon, my Stihl branded oil sold in the states is labeled in oz per gallon. Why we never went metric is beyond me, but we learned it, but never used it. Unless you are in the medical field, as my wife is, then everything is metric, go figure.
Oh, and when I was working we had to convert almost everything, because the machines we serviced that made boxes were almost all European made.


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## maple1 (May 21, 2020)

I use a 5l jug for mix. I dump half a bottle of oil in (100ml) and fill it up not quite full. Around 4.5l. Gives me 45:1. Never any oiling issues, things keep working like they're supposed to.


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## PaulOinMA (May 21, 2020)

My education was in chemistry.  Temperatures are in C, but you always want to know the F equivalent since it is what you grew up with.  Was always converting rough estimates in my head.

C = 5/9 (F -32)

F = 9/5C + 32.


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## brenndatomu (May 21, 2020)

Sodbuster said:


> Math is not my strong suit so how much fuel to add to a 2.6 oz bottle of oil?


For what ratio?
Obviously 50:1 is 1 bottle with 1 gallon...40:1 would be 1 bottle with .8 gallons gas


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## Sodbuster (May 22, 2020)

brenndatomu said:


> For what ratio?
> Obviously 50:1 is 1 bottle with 1 gallon...40:1 would be 1 bottle with .8 gallons gas



Thank you, I think I'll try the 40:1 even though I have no problems. I am always uncertain of the gas pump giving an exactly accurate measurement at 1 gallon, even though they are supposed to.


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## salecker (May 22, 2020)

Sodbuster said:


> Run what the manufacturer calls for any high quality 2 stroke oil will do, Stihl, Husqvarna etc. Don't cheap out on oil.
> 
> 
> 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?


i run 32;1 oil in everything.New saws,ported saws old saws and Antique saws.
so for a 2.6 oz bottle of oil add 83.2 oz of gas(just used the calculator on my phone)which is 1.53846154 of a US gallon.
 With pretty much everyone using a smart phone these days you always have a calculator with you so mixing is a breeze


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## brenndatomu (May 22, 2020)

salecker said:


> so for a 2.6 oz bottle of oil add 83.2 oz of gas(just used the calculator on my phone)which is 1.53846154 of a US gallon.


I think you divided instead of multiplied...or something...32:1 with 2.6 oz oil would be ~.65 gallons of gas...
EDIT: 0.65 gallons is 83.2 oz as you stated...so what is the 1.53846154 gallons that you mention? I so cornfused now...


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## GadDummit (May 22, 2020)

For a 50:1 ratio of gas to oil, use 2.6 fluid ounces of oil per gallon of gas.
For a 40:1 mixture, use 3.2 fluid ounces of oil per gallon of gas.
For a 32:1 mixture, use 4 fluid ounces of oil per gallon of gas.
Most of those small oil bottles are 3.2 fl oz so you'll have to add a bit for 4 fl oz.
I also always run 32/1 because I like my stuff to be well lubricated and last a long, long time. Almost never smokes either.


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## Sodbuster (May 22, 2020)

GadDummit said:


> For a 50:1 ratio of gas to oil, use 2.6 fluid ounces of oil per gallon of gas.
> For a 40:1 mixture, use 3.2 fluid ounces of oil per gallon of gas.
> For a 32:1 mixture, use 4 fluid ounces of oil per gallon of gas.
> Most of those small oil bottles are 3.2 fl oz so you'll have to add a bit for 4 fl oz.
> I also always run 32/1 because I like my stuff to be well lubricated and last a long, long time. Almost never smokes either.



Actually the small ones are 2.6 oz and the larger ones are 12.8 for 5 gallons (50:1)


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## GadDummit (May 22, 2020)

Sodbuster said:


> Actually the small ones are 2.6 oz and the larger ones are 12.8 for 5 gallons (50:1)


My last several bottles had a fill cup at 3.2 oz. Looks like this, but different brand. 




__





						Robot or human?
					





					www.walmart.com


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## brenndatomu (May 22, 2020)

GadDummit said:


> My last several bottles had a fill cup at 3.2 oz. Looks like this, but different brand.
> 
> 
> 
> ...


They are just making it easy to mix 40:1/gallon...


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## Alpine1 (May 22, 2020)

LOL... I’m glad we use the metric system  here:
2% oil mix is 200 ml to 10 liters (9.8 liters to be exact)
3% oil mix is 300 
You can easily make 3.725% if you need to, and have a graduation fine enough on your gas tank


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## ikeepgrnbarsfull (May 22, 2020)

I do fancy myself mechanically inclined. I used to drive a 30 year old diesel S-Class daily and there was always something to wrench on. 

What advice or links can you point me towards to start cleaning this transfer out?

In the meantime, I picked up an MS261 and it rips. I'm absolutely going to run the right fuel in it and probably around 45:1 just to be safe.


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## Sodbuster (May 22, 2020)

ikeepgrnbarsfull said:


> I do fancy myself mechanically inclined. I used to drive a 30 year old diesel S-Class daily and there was always something to wrench on.
> 
> What advice or links can you point me towards to start cleaning this transfer out?
> 
> In the meantime, I picked up an MS261 and it rips. I'm absolutely going to run the right fuel in it and probably around 45:1 just to be safe.



Have the same saw and love it, it's a screamer, and not even completely broken it yet. Full chisel chain and the chips are flying.


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## salecker (May 23, 2020)

brenndatomu said:


> I think you divided instead of multiplied...or something...32:1 with 2.6 oz oil would be ~.65 gallons of gas...
> EDIT: 0.65 gallons is 83.2 oz as you stated...so what is the 1.53846154 gallons that you mention? I so cornfused now...


Yea i know it's confusing,US Gallons, Liters ,Canadien Gallons are all different...
But ounces are all the same...
Using the calculator again who knows where the 1.53846154 comes from
So double check before you commit.


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## salecker (May 23, 2020)

ikeepgrnbarsfull said:


> I do fancy myself mechanically inclined. I used to drive a 30 year old diesel S-Class daily and there was always something to wrench on.
> 
> What advice or links can you point me towards to start cleaning this transfer out?
> 
> In the meantime, I picked up an MS261 and it rips. I'm absolutely going to run the right fuel in it and probably around 45:1 just to be safe.


The best way to clean the transfer off is with a mandrel on a drill or..and sandpaper.
The plating is supper hard so the sandpaper will not damage it,but you have to watch around the port openings.If you were to concentrate on one spot for a lengthy time you may damage the plating.
There is a website Outdoor Power Equipment,look up Masterminds cylinder cleaning thread.
 He has a video to watch as well.


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## brenndatomu (May 23, 2020)

salecker said:


> The best way to clean the transfer off is with a mandrel on a drill or..and sandpaper.


Muriatic acid is the way we did it when I worked at the bike shop and was trying to save a pricey chrome cylinder for someone. A few drops on the aluminum and it will wipe off...may take a few cycles to get clean. BE CAREFUL, you are working with acid...all safety rules need to apply!


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## Sodbuster (May 23, 2020)

brenndatomu said:


> Muriatic acid is the way we did it when I worked at the bike shop and was trying to save a pricey chrome cylinder for someone. A few drops on the aluminum and it will wipe off...may take a few cycles to get clean. BE CAREFUL, you are working with acid...all safety rules need to apply!



I have no idea if this works, but if brenndatomu say's it does I believe him. Just be warned, as he said Muriatic acid is wicked to the nostrils and lungs. When you open the bottle, you'll actually see "vapor" coming out of the bottle. Keep the bottle as far from you as possible and do not breath in.  Eye's and gloves are a must. I used to work in a meat processing plant, and we'd use muriatic acid to de-lime the equipment. Worked great.


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## ben94122 (May 23, 2020)

salecker said:


> Yea i know it's confusing,US Gallons, Liters ,Canadien Gallons are all different...
> But ounces are all the same...
> Using the calculator again who knows where the 1.53846154 comes from
> So double check before you commit.


It's the reciprocal: 
1/1.538 = 0.65
Meaning you have the units upside down someplace. Write the equation out with units next to each number, and make sure each element of the equation is flipped the right way so you end up with the units you want,

Just be careful, because it is a slippery slope from this to dimensional analysis, which is truly the language of the gods.


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## salecker (May 24, 2020)

brenndatomu said:


> Muriatic acid is the way we did it when I worked at the bike shop and was trying to save a pricey chrome cylinder for someone. A few drops on the aluminum and it will wipe off...may take a few cycles to get clean. BE CAREFUL, you are working with acid...all safety rules need to apply!


The problem with acid is if you have a flaw in the plating you will lift it with acid, ruining the cylinder.
If you know what you are doing with acid you can be careful and be fine.But the chances of destroying the cylinder are quite a bit higher,and add some percentage to that if you have never cleaned a cylinder with acid.
After i saw Masterminds way i got rid of my acid,less chance of destroying valuable parts.Once you get into bigger saws the cylinders can cost $300 or more.
Not going to risk that kind of money if the cylinder has a flaw that you don't see,and have the plating lift.You can run a cylinder with a flaw so long as the plating is sound.
 So your choice on the method,how good are you at predicting the level of damage under the aluminum transfer is up to you.If there is a flaw you will not see it till the plating begins to lift.


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## brenndatomu (May 24, 2020)

salecker said:


> The problem with acid is if you have a flaw in the plating you will lift it with acid, ruining the cylinder.
> If you know what you are doing with acid you can be careful and be fine.But the chances of destroying the cylinder are quite a bit higher,and add some percentage to that if you have never cleaned a cylinder with acid.
> After i saw Masterminds way i got rid of my acid,less chance of destroying valuable parts.Once you get into bigger saws the cylinders can cost $300 or more.
> Not going to risk that kind of money if the cylinder has a flaw that you don't see,and have the plating lift.You can run a cylinder with a flaw so long as the plating is sound.
> So your choice on the method,how good are you at predicting the level of damage under the aluminum transfer is up to you.If there is a flaw you will not see it till the plating begins to lift.


I hear ya...never had one lift on me personally...and as far as running something with a flaw, kinda hard for a shop to charge for and stand behind a rebuild with something like that, unless the customer signs off on doing it. We usually recommended getting it re-sleeved if it wasn't "perfect" after acid removal...not an option on everything though I know...


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## DodgyNomad (May 25, 2020)

I run my 2 strokes all a little heavy on oil as well.  42:1, Klotz with ethanol free 93 octane, gives it that nice racing fuel smell too.  Never a problem.


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## ben94122 (May 26, 2020)

Where do you guys find ethanol free gas?


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## johneh (May 26, 2020)

Ethanol Free California





						Ethanol-free gas stations in the U.S. and Canada
					

pure-gas.org is the definitive list of ethanol-free gas stations in the U.S. and Canada




					www.pure-gas.org


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## DodgyNomad (May 26, 2020)

johneh said:


> Ethanol Free California
> 
> 
> 
> ...



Yup, that's the place to look.


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