Stihl ms170 dead - can I warranty?

[chrisfarmwood40]

I bought an ms170 in March of 2021. First brand new chainsaw I ever bought. I loved it, light, lots of power for what I use it for (cutting up dead ash trees mostly, none are very big and use bigger saw for the big ones) And boy did I use it. Used it at least once a week, Have probably put close to 100 litres of gas through it.


And today it died. Used it yesterday to cut a bunch of firewood and thought it ran great. Today just suddenly stopped idling. Thought maybe it was the exhaust screen, but remembered i removed it early on. Took off the exhaust and sure enough the piston is scored to heck.

I am very studious with my fuel mix, always ran it 40:1 with Stihl oil.

First of all, is this normal? Can you just wear out a chainsaw in a year and a half from using it?

Second of all, I told all this to the dealer I bought it from, including the part where I used it a ton. He told me 1 year warranty and he isn't interested in it. New one is $279. My letter from Stihl that I got when I bought it says 2 year warranty.

I don't have a lot of money right now so new chainsaw is not in the cards. Will have to go back to using my Husqvarna 45.

 

[Stock]

Get out your receipt and letter send copies to your dealer and to stihl. After that head to small claims court.....................................................................................

 

[pioneerguy600]

It didn`t score itself, the mixture was wrong
, lean condition caused either mechanically by the carb or an air leak which essentially is a lean condition, too much air for the amount of fuel being ingested. The right amount of fuel mix is what cools the piston, too little fuel and the piston heats up rapidly and hot metal expands making the piston too tight in the cylinder, the tight piston causes too much heat and the aluminum melts and transfers to the cylinder wall thus scoring is the result.

 

[HarleyT]

Old nasty fuel sitting in a saw all summer can do a number on any saw.

 

[coffeebrk]

I'd pursue the warranty also. I've seen complete oem 170 engines on ebay for less than $100 no need for a new saw

 

[chrisfarmwood40]

It didn`t score itself, the mixture was wrong
, lean condition caused either mechanically by the carb or an air leak which essentially is a lean condition, too much air for the amount of fuel being ingested. The right of fuel mix is what cools the piston, too little fuel and the piston heats up rapidly and hot metal expands making the piston too tight in the cylinder, the tight piston causes too much heat and the aluminum melts and transfers to the cylinder wall thus scoring is the result.

What do you think caused lean condition? Always ran fine. I would use it until it ran out of gas often though.

 

[HarleyT]

How old is the fuel that you used?

Be honest now........

 

[cdherman]

"Yesterday it ran great"

"Today it died."

Hmmmm. The story is also not consistent with the usual causes and scenario of bad gas, bad mix, old mix, causing damage to the internals. Scored piston happens over time, loss of power is gradual, unless you really f-up and run pump gas or sumpin'.

Frankly, buddy, your dealer doesn't believe you and neither do I.

 

[stihltech]

The worst thing that people do to a saw is let it sit. Fuel in a saw is junk in 90 days. I do not care what fuel. Also water forms in the fuel. Again i don't care what fuel you are using. The first part of diagnosis of a dead saw is to dump the fuel in a glass jar. Tells the story.

 

[RedneckChainsawRepair]

Homeowner use MS chainsaws, says 1 year. When did stihl ever offer 2 year warranty unless you bought the oil or mix deal to get a double extended warranty? Never heard of that in US. Canada has a 2 year?

 

[Defdice]

Do you let your saw warm up before cutting? Starting them and immediately reving/cutting can cause that, even if you are running 40:1. The piston heats up/expands faster than the cylinder - especially on the exhaust side.

But you don't have to take my word for it, just ask Steve

 

[rocketnorton]

What do you think caused lean condition? Always ran fine. I would use it until it ran out of gas often though.

sounds like the air leak is in the tank, runnin it out of fuel

 

[Catfish044]

I don’t understand this theory , if it’s ran outta fuel or fuel is turned off and the engine consumes that useable energy of the fuel why would it go lean ? The pre , current and after effect of mix is the oil , it’s what’s left on the cylinder walls , rings , bearings . Engines off what’s it wearing ? Always ran every piece of my equipment outta fuel for storage . Race bikes included , never cooked a top end period

 

[ZeroJunk]

If they have a significant air leak they have a noticeable drop in power and they idle at a very high RPM if at all.

Another thread about goosing the saw out of the cut, I do that sometimes just to periodically check the tune.

I have had seal go bad and just chased it with a screwdriver until I finished what I was doing.

Your MS170 likely had no carb adjustment at all other than idle speed. So, if the manifold pulled loose, or I have even seen them with a stick stuck through them....

It's a little hard for the dealer to chase finding something when 95% of the time it is straight gassed, and 95% of the time they say it wasn't, and 95% of the time once they realize thhey did they dump the gas out and put mix in. Dead give away when the tank is full.

 

[buzz sawyer]

I just rebuilt one, leaking at the clamshell seams. It could also leak at the boot and where the carb seats against the boot. There is a little plastic ring that I believe keeps the boot from collapsing under acceleration. It was installed poorly and may have been leaking. The carb has fixed H and L jets so you can't adjust. You have to listen for 4 stroke every time you run it. It could also have picked up some dirt in the inlet screen in the carb and caused a lean condition.

 

[pioneerguy600]

What do you think caused lean condition? Always ran fine. I would use it until it ran out of gas often though.

I have seen a few torn up 170`s and later found out from the owners that they were running them more than 3 minutes in big wood under heavy load, the cheap non adjustable carbs cannot deliver enough fuel under heavy load to keep the piston cooled, dull chains also played a part in overheating them. The 170`s with good sharp chains and used as a trimming saw lasts much longer than those used for heavy bucking of larger diameter wood.Several 170`s have come in that were used for bucking hardwood, some sticks over 20" dia, they were badly scored.

 

[SteveSr]

What do you think caused lean condition? Always ran fine. I would use it until it ran out of gas often though.

Removing the spark arrestor lessens the muffler restriction causing it to lean out. Running 40:1 instead of 50:1 doesn't help either. More oil = less gas.

 

[dmb2613]

If you fix that one or get another 170 , run it 50 to 1 with the Stihl mix. The saw will like it. And like others have said, that saw is not made for the amount of cutting you seam to be doing

 

[buzz sawyer]

I don’t understand this theory , if it’s ran outta fuel or fuel is turned off and the engine consumes that useable energy of the fuel why would it go lean ? The pre , current and after effect of mix is the oil , it’s what’s left on the cylinder walls , rings , bearings . Engines off what’s it wearing ? Always ran every piece of my equipment outta fuel for storage . Race bikes included , never cooked a top end period

I also run mine out of fuel for storage - but only at idle. If you run WOT in a cut as it runs out, you can hear it go lean and speed up - not good.

 

[Captain Bruce]

What do you think caused lean condition? Always ran fine. I would use it until it ran out of gas often though.

40:1 and premium gas, and Stihl mix oil. Cheap out on fuel, and be lazy as to servicing. and the saw will lay down and die. The air filters allow dirt into the cylinder.........and buying the cheapest gas, and using some cheese-ball oil for a buck a bottle.....thats a sure way to ruin any 2-cycle engine. The 170's are fun saws, All they ask is to be used, and operated, correctly...