How to service a stihl ms250

[Grant1994]

I have a 4 year old ms250 that gets pretty frequent use yet has only been service once. I am trying to keep costs down as well as begin to learn more about mechanics so I was wondering if anyone out there could tell me all the things that I could do to service this saw myself and how to do them?

Thanks,
John

 

[Fixemall]

Remove the Bar and Chain, hose them down separately with warm water and mild detergent, blow dry with compressed air, pay close attention to getting the bar groove and oil passages clean, grease sprocket tip and spray chain and bar with fluid film to prevent rust. As to the powerhead, blow it clean with compressed air and use a stiff paintbrush for stubborn areas, pay special attention to the clutch and cooling fins. Now you are ready to remove the air cleaner cover and air cleaner, plug the carb with a rolled up rubber glove to prevent chips etc from entering the cylinder, use compressed air to clean around the carb and air cleaner, remove the glove and reassemble. Replace spark plug with recommended one from owners manual. Drain fuel and fish out tank gas filter, replace with new one. Add 1/2 tank of sea foam(no fuel yet) start and run till it smokes like crazy, shut down for at least 12hrs. Drain remaining sea foam, reinstall Bar and Chain, add fresh fuel and bar oil, run till remaining smoke clears and verify bar oiling by running at WOT in front of a log and look for a stream of cast off oil. Now is a good time to sharpen chain, if you are not comfortable doing it on your own, send it out during the sea foam delay.

 

[MotorSeven]

Don't forget to look at the sprocket, if it has significant wear replace it and the chain at the same time. Also, look at the edge of the bar for wear, and if needed dress the bar. Bar's can get worn on one side of one edge more than the other. This will cause it to cut crooked.
Wash the air filter in Simple Green and a brush with a very SOFT tooth brush(a stiff brush will remove the flocking), rinse and pat dry. Look at the fuel line and impulse line(if it has one)
You can avoid fuel related issues by adding Marine Stabil(green stuff) to you saw fuel. It kills ethanol which is what causes most carb gumming. Wallyworld sells it, and I use it on all my small engines.

 

[turnkey4099]

To add to theothers:

If you aregoing to store it for a week or more, dump the fuel, start it and let it run until it dies.

Cleaning bar groove. Best is one of the depth gauge file guides that has the 'bar cleaning hooks' on one end. Mine is Stihl. any dealer should have one and they are only a buck or two. You need one anyhow for lowering the rakers when shaprening chain.

When blowing stuff off the bar, pay attention to the very small oiler holes, make sure you can see through them.

Flop the bar over everytime you remove the chain - evens out the wear on it. I use a magic marker to put an arrow point up on the bar before I remove it. That way I can tell to put it back on "arrow down".

I cut 10 plus cords/yr and been at it for 35 years now. Most cleanup I do on the saws is a good blow out with compressed air. Scrubbing saws/bars with soap water is getting a bit **** IMO.

Harry K