MS250

[Opihi59]

Just FYI- Last time I checked ( this fall) new OEM C1Q-S76 carbs were $35 at my local Stihl dealer. At that price it barely makes sense to try and rebuild the carb.

That may become necessary, if I don't manage to get adequate results on the D/G kit. Of course, I live on a very small island in the middle of the Pacific Ocean and it is unlikely that I would be able to get pricing ladat here. But.....I do have mainland contacts, and I do travel.

 

[Opihi59]

Okay, filling all interested parties in on the latest. The D/G kit did show up in the mail finally, it is now installed and the saw is starting up very easily and runs fine. Thanks for all the help thus far.

So now it is running easily and I have noticed it is leaking bar oil out from below/drive side under the muffler. It does oil the chain thru the proper orifice, but this is a leak from a hole/aperture/orifice/foramina that to me seems it should have a cap of some sort. The inside of the hole is not threaded; it appears that whatever was once there is gone, and bar oil wells up here to a significant degree. The hole is right at the tip of the screwdriver.

Edit-I do feel compelled to mention I read a bunch of 250 oiling problem threads, most mentioned misalignment of oiling hole with hole in bars, but there was enough mention of an oil tank vent valve mentioned to be "under the muffler." There were no photos of this, and several questions were asked, but the threads thereafter died.

Anyone have any insight here? Diagrams, part number, etc? Thanks!!

 

[ZeroJunk]

Okay, filling all interested parties in on the latest. The D/G kit did show up in the mail finally, it is now installed and the saw is starting up very easily and runs fine. Thanks for all the help thus far.

So now it is running easily and I have noticed it is leaking bar oil out from below/drive side under the muffler. It does oil the chain thru the proper orifice, but this is a leak from a hole/aperture/orifice/foramina that to me seems it should have a cap of some sort. The inside of the hole is not threaded; it appears that whatever was once there is gone, and bar oil wells up here to a significant degree. The hole is right at the tip of the screwdriver.

Edit-I do feel compelled to mention I read a bunch of 250 oiling problem threads, most mentioned misalignment of oiling hole with hole in bars, but there was enough mention of an oil tank vent valve mentioned to be "under the muffler." There were no photos of this, and several questions were asked, but the threads thereafter died.

Anyone have any insight here? Diagrams, part number, etc? Thanks!!

Yeah, I think it is a 5 MM Allen screw that you can plug it with. Don't get carried away or you will split it.

Just need to plug it is all.

 

[GMB74]

Here's a thread on the subject:

https://www.arboristsite.com/thread...on-the-rear-right-side-of-the-muffler.370318/

Originally there was a plastic plug capping off the passage. It has fallen out.
Install a very short (M6 x 8) allen/grub screw in its place. If the screw is too long it will plug off the passage to the oiler hole.
A 1/4-28 X 1/4 allen screw will work if you tap the hole first.

 

[Opihi59]

Thanks for the responses. I've gone thru a bunch of IPL sites (Itemized Part list) for the MS 250 and have not seen this part mentioned, nor have I been able to search for the proper Nomenclature by using a variety of terms. I suppose I can cut some threads in the hole and thread in a set screw/grub screw.

The vent hole will allow a #5 0.205" drill bit which is 5.207mm, looking at my machinery handbook it tells me that a 6mm 1.0 pitch screw requires a 5.2mm pilot hole, or 0.2047" so I think I'll be fine in tapping 6mm x 1.0 pitch threads in there and installing a short set screw. I need to go dig thru my box o taps to make sure I have that dimension and I'll let everyone know how it goes once I can verify somewhere on my island I can find that set screw........

 

[Opihi59]

So Stihl has a part number for a 6mm set screw, ostensibly for this hole, grub screw part number 000 953 1001. Thanks @GMB74 I'm glad that my calcs matched what Stihl was doing, and I appreciate you linking the thread to me. I'll fill everyone in on the outcome, I'm just not cutting threads in there untill I have the set screw in my hand.

 

[stihltech]

Common issue on those. Could not get the set screw from stihl last I checked. Went to the 1/4 28 mentioned above. just make sure it does not go in too far and block the outlet.
Stihl recommended sealing it with Loctite thread locker.. I believe it was blue, Not all that fussy.

 

[Kdavis2685]

If it were me, I would put a small dab of RTV silicone in there. Should be a relatively long lasting fix, without worrying about damaging anything. You could always use a pick to remove it later.

 

[Automan]

Maybe not for this 250, but the manuals I have shows this is oiler amount screw.
In for less out for more oil to bar?

 

[GMB74]

I doubt that a dab of RTV will hold up very long in this application.
The oiler on an MS250 is not adjustable.

 

[Opihi59]

I tapped that hole 6mm X1.0 and threaded in a set screw, taking care not to sink it too deep and obstruct the oiler hole. I think this saw is now pretty much fixed and can get it back to my buddy.

Thank you all for your help and attention in fixing this saw!

 

[stihltech]

If it were me, I would put a small dab of RTV silicone in there. Should be a relatively long lasting fix, without worrying about damaging anything. You could always use a pick to remove it later.

RTV won't work well as this is the pressure side of the pump circuit.

 

[StihlsawuserMS361]

A thought...maybe in addition to a Loc-tite product, maybe just kiss the plastic a little with a soldering iron to ensure the plug stays plugged?

 

[hotshot]

Good job getting that German saw repaired!

Do you ever cut with the old Craftsman 3.7 Roper made chainsaws from the epic repair threads you made a few years back?

 

[stihltech]

The set screw is the Stihl authorized repair. It works and is permanent.

 

[Opihi59]

@hotshot , regarding the Roper 3.7s I use all of the ones I have repaired quite a bit. They are runners/workers though living on Oahu I do not have a great deal of timber to cut. I do look for blown down trees, do some cutting for friends, and gather mango, lychee, Kiawe, etc. I also slab out Monkey Pod as needed for projects. Recently I used one I had sent my son and helped cut his farm out from the NC hurricane damage on his farm. Those saws do scream. I have upgraded the drive sprockets to a Huskvarna model that allows me to run 3/8 chain, and a 20" bar from the original .325/18" I have found this to be a very legitimate upgrade, and they pull this with no issues.
The only Issue I am having with the Ropers is the bar lubing.....there is a small duck bill valve in the system that has deteriorated so I must use an oil can on them. This is cumbersome at best, especially if climbing. I need to come up with a source for these small valves to get the most out of my Roper pile.

 

[hotshot]

Good deal. Yeah we looked for the bigger duckbills, even through beer brewing equipment & keg taps, but nothing was ever found.