Stihl MS 250 Chain Saw Problems

[platefire]

My first Stihl Was a 011AV with 16" Bar purchased new in 1986. It finally played out in 2018. So 32 years of good solid trouble free
service is why I went Stihl again. I never had to rely on their service tech because it was always working. I changed the bar and chain a couple of
times, but that's it.

 

[Auto Doc's]

Hello platefire,

Be aware that the old saws were much more forgiving and had more size and power. The carburetor passages were larger. They also belched more smoke than they do today. EPA regulations have starved many small engines down.

Do yourself a favor, if you have not already, and use No-Ethanol fuel and the Stihl oil. Mix the fuel exactly as instructed in a steel 1-gallon can. No guess work or estimation to the mix, because the carburetor and newer spark plug designs will cause a terrible hard start. The steel (paint thinner) can with a good screw on lid will preserve the mix much longer than any plastic fuel container ever will.

Don't use the old cheap straight weight oil mix methods like we used to years ago. It will cause you much grief.

I have had to pull many mufflers off of chainsaws and weed eaters to heat the red hot to burn out all the oil coking. The wrong oil mix will choke up a modern muffler quickly.

With 2-stroke engines, the basic rule is: "If old burnt carbon exhaust air cannot get out, new fresh air cannot get in to draw the fuel in."

I've had many Stihl dealers "condemned" saws come to me for a second opinion and it was poor fuel mix related about 80% of the time.

 

[Tiger Small Engine]

Rivets, that is the same procedure in my Stihl MS250 Manual and what I follow most of the time but---when that
don't work? I usually let it sit a while and try that procedure again and it usually fires up. This time none of that
procedure would work for me and it was a reason, the Ignition Module was out and was replaced. I cranked and
ran well for me to do one job last week. Then this week it was acting just like it did when the ignition module
was out----just dead. So I'm glad it's working now because I really like this saw.

On funny note----before I took it to the Stihl Dealer I called a local repairman that I had used years before to get him to work on my saw. The
second I told him it was a Stihl his whole demeanor changed and he was angry! He said I don't work on Stihls and he told me
about the Stihl dealer in town that I didn't know we had--so I appreciate that. I wanted to ask him why he felt that way about
Stihls but by the sound in his voice, I decided to leave it alone:>)

I love working on Stihl equipment! Stihl is the most common handheld equipment in my area. My success rate for getting Stihl equipment starting and running well is very high as long as there is good compression.

 

[slomo]

Sounds like the needle is passing excess fuel possibly. 7 year old carb probably needs a rebuild.

 

[MParr]

Sounds like the needle is passing excess fuel possibly. 7 year old carb probably needs a rebuild.

Could be.
My old SRM225 is hard to start after running a while and putting it down for a few minutes. I imagine that the diaphragms in the carburetor are perished. I replaced all of the fuel lines last year. I may just buy an OE carburetor and be done with it.

 

[platefire]

Well I have to confess, have been using regular gas with Lucus mixed in and using other kinds of oil to the 50:1 mix
other than Stihl oil. So I know that's not prime like using non Ethanol gas and Stihl oil mixture