# Stihl MS250 oiling problem



## vetteboi88 (Jan 20, 2009)

The other day when I was cutting, my chain started to run dry and I still had 3/4+ of a tank of bar oil. I have cleaned the bar and saw body, inspected the filter in the oil tank and cleaned it. If I have the saw running and push in the check valve on the chainside of the saw, bar oil will come out of the check valve, but it's kinda foamy. I've tried my best to clean out the oil passage on the saw, but without disassembling it, I think I'm out of luck.

I think the pump still works, since I get the foam pushed out of the check valve if I depress the valve. Could it be that I have some internal blockage? How can this be cleaned? Do I have to disassemble the saw to do so? Would this be covered under warranty? The saw was purchased new in september. 

Thanks for your help. I'm glad I found this forum. Now I know more about chainsaws than I every dreamed of knowing, lol.


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## resotek (Jan 20, 2009)

How did you clean the bar groove? I run a piece of .050 aluminum down along the bottom of the groove and it comes out full of impacted wood/oil sludge. This is usually the cause if my 250 starts oiling less than it should. Otherwise, I'd take the bar and chain off and run the saw. You'll know pretty quick weather it's oiling or not.

-Mel


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## vetteboi88 (Jan 21, 2009)

I'm SURE it's not oiling. There is no oil coming from the oiling orifice except for the occasional air bubble. If I depress the check valve with the saw runnng, there is a some foamy oil that comes out, followed by oil. I flushed the oil tank with fuel mix and now have some dyed oil in there to help visualize the oil flow and there is NONE.

I clean my bar with a dentist pick and stiff bristled brush.


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## superfire (Jan 21, 2009)

*idea*

start by drain all the oil out of the tank. then wash the tank out with some fuel/oil mix. start the saw with new oil mixed with a little fuel/oil mix( do this with out bar and chain) also pull the muffler and see if the tank vent is plugged.


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## windthrown (Jan 21, 2009)

I do not understand what you mean by a check valve on a 250. To check the oil flow on a 250 (or a 210 or 230, which make up the 1123 line of Stihl saws), pull off the bar and chain and run the saw. If there is no flow out the oil hole, and you cleaned the oil tank filter, then it can be several other things. If there is oil flow at the oil hole of the saw, then clean out the oil holes in the bar and you are done. Otherwise...

One possibility is a clogged oil tank vent valve. The vent is just in front of the bar studs. Use a compressor and blow on the vent from the outside to clear it. The next possibility is a clogged oil line. I have found that after a lot of use in dusty conditions, fines can build up below the oil pump in the 1123 saws. They are a pain to get to. You have to pull the top handle off the saw to get to the small oiler elbow at the bottom of the saw on its belly. Pull the elbow and use a blast of compressed air to clear the elbow. Then pull the oil line out of the hole that one end of the elbow fits into. Check for clogs or breaks in the line. Replace it if needed. Then check the area below the oil pump in the belly of the saw body. That is where I have seen the fines most commonly build up, and clog the oil flow, leading to foamy oiler output. The oil has to run through a small groove that runs along the side of the oil pump, and that is where clogs can and do occur. 

If you cannot clear the fines below or in the oil pump with a compressor, then you have to pull the oil pump. You can buy the fancy spendy Stihl oil pump puller, or get a screw or bolt with the same fine threads as the oil pump base. I have one in my 250 parts bag, but I do not know the pitch or size of the threads. It is about an inch long though. The oil pump has threads at the base, and you screw the screw or bolt into the threads and use a hammer or crowbar to lever up on the screwhead and pull out the pump. The pump is tiny and made of chromed brass, and it is just pressed into place in the plastic case. Once levered out, you can clean it up, blow out the upper oil lines, and then press the oil pump back into place. Align the groove in the oil pump up with the groove in the case, and tap on the screw that you pulled the oil pump out with to seat the pump. Seat the pump in place so that the gears on the oil pump head are at the center of the oil pump drive gear (which is where the oil pump base is about 1/8 of an inch below the level of the case). 

If that does not fix the problem, it may be a warn drive gear, or a broken oil pump drive. The oil pump drive is a thick wire that sits into a notch of the clutch drum. To check the oil drive and gear you have to pull the clutch drum and clutch (remember that the clutch is reverse threaded!). Once inside the clutch area you will see the oil drive and gear which are obvious, and you will see the gear head of the oil pump as well. Spin the drive and check that the oil pump gead head is spinning. In your case, as the oiler is foaming, the oil pump drive and gear are more than likely working, and your problem is a clog in the line someplace. 

Good luck Mr Phelps, and should you or any of your team be caught or captured, the Secretary will disavow any knowledge that I told you anything about fixing the oil pump on a Stihl 1123 saw. :greenchainsaw:

BTW: there is no need to pull the muffler to deal with an oiler on a 1123 saw that I am aware of. ??? *Shrug*


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## vetteboi88 (Jan 21, 2009)

The part which I am referring to as the "check valve" is the vent valve for the oil tank. The silver plug with a small hole, located directly in front of the bar studs. If I press vent with a pin while the saw is running, even at idle, a little foamy oil will be released, followed by oil. 

I have cleaned the oil tank with fuel/oil mix and pulled and cleaned the oil pickup in the tank. I believe I have a clog somewhere. Unfortunately I don't have access to an air compressor so I can't blow anything out. 

Any thoughts to taking this back to the dealer? I really don't want to spend much to repair this as the saw is fairly new, about 10 tanks of fuel so far. I might as well throw the saw away if this is going to be a repeated problem. I'm heating my house with wood exclusively and need to be cutting every weekend.


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## superfire (Jan 21, 2009)

*another?*

did you buy new? how old is the saw? if you bought it new from the dealer give them chance to look at the saw. if you bought less then 12 months it should be under the warranty time.


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## windthrown (Jan 21, 2009)

Air should be sucked INTO the vent, into the oil tank. It should not be going out the vent hole. 

If the saw is that new, it should be covered under warantee. New Stihls are waranteed for a year for homeowner use, 6 months for commercial use. I would take it back to the dealer. It may be something was not put together right. Like the oil pump being installed wrong. There should not be any fines clogging up the oil pump that soon. 

If you want to work on your own saws, just routine stuff, I would get a small compressor. Even a used one on CL like I did. Blow out your air filters, oil and gas lines, clean up sawdust, bar rails, etc. is fast and easy with a compressor. Also from my experience of heating with wood (10 cords a year) and using saws for firewood and all, a 250 is pretty light duty to be a reliable saw for every weekend use. A 260 or a 361 would serve you far better (I have owned and used all of these saws, BTW). Just my 2 cents worth.


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## vetteboi88 (Jan 21, 2009)

Thanks for the replys. Saw is going back to the dealer tomorrow. I just wanted to see if it was something simple that I could fix myself.


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## Nosmo (Apr 30, 2009)

*Ms 250*



superfire said:


> start by drain all the oil out of the tank. then wash the tank out with some fuel/oil mix. start the saw with new oil mixed with a little fuel/oil mix( do this with out bar and chain) also pull the muffler and see if the tank vent is plugged.



I am wondering about this piece too. I know where that object is you are talking about and it is visible when the muffler is removed and it does look like a valve. I am having oiling problems with my 
MS 250C too. I am going to replace the vent valve just in front of the bar stud. 

With the elbow removed on the underside of the tank is it OK to blow air into the pump chamber ? 

Nosmo


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## Nosmo (Apr 30, 2009)

*Valve or ?*

I forgot to ask -- what is that piece on top of the tank under the muffler that looks like a valve ?

Nosmo


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## Nosmo (May 15, 2009)

*Valve or ?*

Well I never did find out what that piece is . But I do have the MS 250C oiling like it should.

Nosmo


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