Stihl MS250 rebuild.

[sd455dan]

thread bump,

Dave have you gotten some run time on the rebuild? How's the saw performing?

 

[dodge man]

I have used it some but not a lot. The power and idle is really good. I originally thought it ran fine at full throttle but wouldn’t idle before the rebuild. Looking back after the rebuild it wasn’t making good power. It is running much stronger now. I bought a MS261 a few months back and it is a entry level professional grade saw so the MS250 is a backup saw for me but I haven’t used either much lately. Next time I cut I will probably use both.

 

[sd455dan]

Interesting you mentioned the idle. before the rebuild,

Just worked on a Stihl 311 for a friend.

Was driving him nuts trying to get much firewood cut, said he has been about to pull his hair out.
Running the saw and even think about setting it down and it would die then maybe not restart.

Weird ignition problem, had spark but only when pulling the starter cord really hard and fast.

Saw would run good above idle but miss intermittently at idle.
Did the coil electrical tests cleaned connections and also checked flywheel to the electronic magneto clearance -all good.

Finally just ordered up a replacement and installed it. First slow pull test with the plug out and nice consistent hot spark. Sure enough something was screwy with the electronics. He is happy to be cutting wood again.

Glad to hear the 250 is running good and strong now.

 

[dodge man]

A pic looking in the exhaust port before the rebuild.

 

[sd455dan]

OUCH...

It Sure is nice that the Stihl and Husky saws have great parts availability from MFGr and aftermarket

 

[dodge man]

I’ve kind of turned this original problem over in my head, what caused the cylinder and piston scoring? The general consensus seemed to be no oil in the fuel. Possible but I keep my 2 stroke fuel in a 2 gallon can and the only other gas in a 5 gallon can. I have several 2 stroke engines, a lawn boy, weed eater, leaf blower, pole saw, so if I just forgot the oil, I would think I would have burned one of them up. My son used the saw some at my place, he could have put straight gas in but it’s awkward from the 5 gallon can. I am almost positive I didn’t.

So several years ago I started using Amsoil 2 stroke. They SWEAR you can run it at 100 to 1 no matter what it is suppose to be. I did this for a while. I don’t remember how long, maybe a year or two. The chainsaw is the only one of my two stroke stuff that gets used hard. After a while this didn’t feel right so I still use the Amsoil stuff along with the Stihl oil but always at 50 to 1. This all took place several years ago but my saw had been running bad for a while. I’ve also noticed Amsoil doesn’t seem to be pushing the 100 to 1 thing like the used to. So did I ruin my saw by running 100 to 1 Amsoil mix?

 

[sd455dan]

I致e kind of turned this original problem over in my head, what caused the cylinder and piston scoring? The general consensus seemed to be no oil in the fuel. Possible but I keep my 2 stroke fuel in a 2 gallon can and the only other gas in a 5 gallon can. I have several 2 stroke engines, a lawn boy, weed eater, leaf blower, pole saw, so if I just forgot the oil, I would think I would have burned one of them up. My son used the saw some at my place, he could have put straight gas in but it痴 awkward from the 5 gallon can. I am almost positive I didn稚.




So several years ago I started using Amsoil 2 stroke. They SWEAR you can run it at 100 to 1 no matter what it is suppose to be. I did this for a while. I don稚 remember how long, maybe a year or two. The chainsaw is the only one of my two stroke stuff that gets used hard. After a while this didn稚 feel right so I still use the Amsoil stuff along with the Stihl oil but always at 50 to 1. This all took place several years ago but my saw had been running bad for a while. I致e also noticed Amsoil doesn稚 seem to be pushing the 100 to 1 thing like the used to. So did I ruin my saw by running 100 to 1 Amsoil mix?

used to do the work on my Brothers YZ dirt bikes when he raced, early on we ran Klotz synthetic, he wanted to go trail riding 1 day no klotz.
A friend lent him whatever mix he was running and it gummed up the piston cylinder and lost compression.

later had just rebuilt my Husky 250 WR dirt bike, (fully broken in with several full day ridings) brother borrowed it without asking...
Ran out of the Bel Ray MC-1 up in the woods, I was running (and still run in bikes and saws) a logger gave him whatever mix he was running and it burned up the Husky including breaking the ring and scoring the cylinder.

Most these oil mix companies say they are compatible but i do not ever do it anymore.

I just order up multiple bottles of MC-1 and run it just over the recommended 50 to 1 @ 45 to 1 almost no smoke and i have always liked the way it smells.

anyway a big believer in not switching out the premix oils. Going to stick with MC-1 even my old McCulloch Promac 700 likes it. i don't have any Auto tune or computer controlled 2 strokes, If I did I would not run the MC-1 in them because for newer 2 strokes they have another product.

Amzoil is REALLY good stuff for sure to.

I would never run any 2 stroke that lean "oil to fuel wise", of 100 : 1
If nothing else I would think it would affect the fuel viscosity enough to make tuning the saws Hi and low needles more touchy.

 

[Bearsixty7]

I致e kind of turned this original problem over in my head, what caused the cylinder and piston scoring? The general consensus seemed to be no oil in the fuel. Possible but I keep my 2 stroke fuel in a 2 gallon can and the only other gas in a 5 gallon can. I have several 2 stroke engines, a lawn boy, weed eater, leaf blower, pole saw, so if I just forgot the oil, I would think I would have burned one of them up. My son used the saw some at my place, he could have put straight gas in but it痴 awkward from the 5 gallon can. I am almost positive I didn稚.

So several years ago I started using Amsoil 2 stroke. They SWEAR you can run it at 100 to 1 no matter what it is suppose to be. I did this for a while. I don稚 remember how long, maybe a year or two. The chainsaw is the only one of my two stroke stuff that gets used hard. After a while this didn稚 feel right so I still use the Amsoil stuff along with the Stihl oil but always at 50 to 1. This all took place several years ago but my saw had been running bad for a while. I致e also noticed Amsoil doesn稚 seem to be pushing the 100 to 1 thing like the used to. So did I ruin my saw by running 100 to 1 Amsoil mix?

Not likely. If it was Amsoil SABERｮ Professional Synthetic 2-Stroke Oil. It has been tested to the extreme, they did a limit test on it a while back and were able to run it at 300:1 ratio and the test engines/piston's and walls were all in great shape. However they said no one would believe a 300:1 ration would offer enough protection so they kept it labeled 100:1, still is today.
I have ran it for many years in an Echo PAS 225 weedeater/leafblower, a craftsman 18" chainsaw (~24 years old now) and recently a Huskvarna 55 chainsaw at 100:1 and they all start easily and smoke is near undetectable.

 

[dodge man]

It was the Amsoil Saber two stroke oil. I still have quite a bit of it and will run it 50 to 1.

 

[art]

. I bought a MS261 a few months back and it is a entry level professional grade saw so the MS250 is a backup saw for me but I haven’t used either much lately. Next time I cut I will probably use both.

Stihl builds many sizes of pro saws. The size you bought is actually the third size up from the smallest in the pro line. Many use them in pulp wood in this area but they are also used on cull log loads for fire wood and are a pro saw not an entry level.