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Stihl 026 Chainsaw hard to crank - retrofit compression relief valve?

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  • Stihl 026 Chainsaw hard to crank - retrofit compression relief valve?

    I've been working on a Stihl 026 chainsaw that John found, and it is very hard to crank. The manual for this model, and the parts breakdown, show a compression release valve. But the saw just has a rubber piece on the top shroud with a slotted nut that just fastens it to a stud on the cylinder head, where the valve should be. I took the saw to a local dealer who said that nut was the compression relief, and should have been adjusted at the factory or by repair personnel, but obviously he was mistaken. He was able to crank the saw, and said it had good compression. I removed the spark plug and was able to see a spark when I cranked it, so it should probably start if I can crank it fast enough (assuming carburetor and fuel system are OK).

    I found replacement valves for less than $10: https://www.ebay.com/b/STIHL-Chainsa...915/bn_7893410

    And a video that might help, but I haven't watched it yet:



    I'm looking for advice or experience about perhaps pulling the cylinder head and retrofitting a valve. Pictures of what I have.

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    http://pauleschoen.com/pix/PM08_P76_P54.png
    Paul , P S Technology, Inc. and MrTibbs
    USA Maryland 21030

  • #2
    Paul I would personally recommend against it. If the saw now has excellent compression as you say, I would find a starting regime that works well for you once you get the tune dialed in.
    You will need to replace the entire top end of the saw in order to get the decompression valve, as the run of the mill 026 did not come with the decomp valve, only the 026 Pro did I believe.

    The engine does not have a separate cylinder head as such but instead shares the cylinder and head as one unit, as do most chainsaws.This and the piston and rings should be replaced as a set. Running the old piston with the new cylinder can turn into an expensive lesson most times.

    Also when doing these you need to be very strict about cleanliness before before taking the saw apart. Dirt and debris in the crankcase can cause all manor of issues down the road including but not limited to wear on the needle bearings, main ball bearings and leaky crank seals. All of these will require a major and expensive rebuild.

    Lastly I would find another dealer as it seems the one you talked to has absolutely no idea what he is looking at.

    Good luck Paul, sounds like the saw is mechanically sound which is 90% of the battle. Get it dial in and find a system for starting that works for you, you'll be time and money ahead.
    Home, down in the valley behind the Red Angus
    Bad Decisions Make Good Stories​

    Location: British Columbia

    Comment


    • #3
      How many ccs is it? I have an MS260, 50cc without compression release and it is hard for me to start. The release is optional. I don't know if one can be easily retrofitted. Older models did not have a priming feature and take a lot of cranking to get gas flowing. I have seen service people squirt a little gas in the carb to get a dry saw going. They don't have to turn fast to start. I bought a new Still with primer and easy crank start. Big improvement for old fart. I know manual says to engage brake to start but I always have brake off for starting. Just keep clear of chain when you start.

      Comment


      • #4
        I have thought about making some way to use a drill to crank the saw for starting, but that does not look to be easy. The hard part is holding the body and handle of the saw while pulling the rope. The manual shows the "usual" method of holding the saw with your foot through the handle, and an alternate method of holding it between your knees. My shoe doesn't seem to fit very well through the handle, but maybe I could use a piece of wood to provide a more stable platform.

        I saw something about a compression release spark plug, but the article did not confirm its existence. However, it did discuss the possibility of adding a compression release. It also mentioned an "elasto-start" rope. They are available for $32 but the 026 model is not listed. Maybe I can just add an extension spring on the existing rope?

        There are also EZ-Start spark plugs, which have sharper fine wire and ground electrodes that help the arc to form more readily.

        http://pauleschoen.com/pix/PM08_P76_P54.png
        Paul , P S Technology, Inc. and MrTibbs
        USA Maryland 21030

        Comment


        • #5
          May not solve your issue but have a friend that rescued a riding lawn mower that was burning up starters from his neighbors trash. Neighbor said he was fed up he could have it. Sticky compression release valve was the problem. My buddy is a good practical mechanic considered the difficulty replacing. Sprayed it with carb cleaner then WD40. Cranks fine & he’s been using it for several years

          Comment


          • #6
            Originally posted by PStechPaul View Post
            I have thought about making some way to use a drill to crank the saw for starting, but that does not look to be easy. The hard part is holding the body and handle of the saw while pulling the rope. The manual shows the "usual" method of holding the saw with your foot through the handle, and an alternate method of holding it between your knees. My shoe doesn't seem to fit very well through the handle, but maybe I could use a piece of wood to provide a more stable platform.
            My old McCullough saw I could easily get my booted foot through the handle. My new MS 250 no such luck. I have never been much on holding it at waist level and starting it like a lot of folks do. I found that if I lean on the handle a bit it will stay on the ground enough for me to start it.
            Tom - Spotsylvania, VA

            Comment


            • #7
              Originally posted by PStechPaul View Post
              I've been working on a Stihl 026 chainsaw that John found, and it is very hard to crank. The manual for this model, and the parts breakdown, show a compression release valve. But the saw just has a rubber piece on the top shroud with a slotted nut that just fastens it to a stud on the cylinder head, where the valve should be. I took the saw to a local dealer who said that nut was the compression relief, and should have been adjusted at the factory or by repair personnel, but obviously he was mistaken. He was able to crank the saw, and said it had good compression. I removed the spark plug and was able to see a spark when I cranked it, so it should probably start if I can crank it fast enough (assuming carburetor and fuel system are OK).

              I found replacement valves for less than $10: https://www.ebay.com/b/STIHL-Chainsa...915/bn_7893410

              And a video that might help, but I haven't watched it yet:



              I'm looking for advice or experience about perhaps pulling the cylinder head and retrofitting a valve. Pictures of what I have.

              Click image for larger version

Name:	Stihl_Chainsaw_6946.jpg
Views:	604
Size:	239.8 KB
ID:	1983082
              Click image for larger version

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Views:	597
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ID:	1983079
              Click image for larger version

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Views:	638
Size:	141.1 KB
ID:	1983078
              Click image for larger version

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Views:	610
Size:	170.3 KB
ID:	1983080
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ID:	1983081
              What Willy said. That saw does not need a decompression valve anyways.
              You need a different technique, use the weight of the saw to drop start it. I have a MS460 (76cc) I like with a 32" bar. I threw away the decomp and put a plug in it as it not needed and didnt seal properly.
              Practice makes perfect.
              Cheers,
              Jon
              Attached Files

              Comment


              • #8
                Originally posted by Jon Heron View Post

                I have a MS460 (76cc) I like with a 32" bar.
                AKA "Widowmaker"
                Tom - Spotsylvania, VA

                Comment


                • #9
                  I have the same saw WITH the MANUALl compression release. If I don't set the compression release, I can just about start it. With the compression release set, it starts easily.
                  Peter
                  Grantham, New Hampshire

                  Comment


                  • #10
                    Paul it sounds and looks like that the saw is not running yet. My advice is to get someone that is familiar with chainsaws, another dealer perhaps, to get the saw running and starting reliably first. No sense wearing yourself out on a dead horse so to speak. If the saw is not starting right now or hasn't run for a while it may need some carb work etc., who knows?

                    At the moment it is an unknown quantity and unless you are very experienced at this sort of thing the saw can wear you out while you learn, so get someone to set it up properly. You want a saw not a hobby or a fitness and agility test.

                    Once it is dialed in build a jig of sorts that you can set the saw in so that it is secure and comfortable for you to start when pulled. Other than that my only other suggestion would be for you to trade the saw in on something smaller.
                    Home, down in the valley behind the Red Angus
                    Bad Decisions Make Good Stories​

                    Location: British Columbia

                    Comment


                    • #11
                      Honorable mention here in leverage ratio's,

                      make sure you have the MAXIMUM amount of pull rope as it's single file stacked, what this does for you is give you the "first pull variable leverage ratio advantage" as you have effectively changed the pulley diameter ratio in your favor,
                      and yes it will taper down as you pull but now you have a little flywheel momentum on your side....

                      Edit; While im at the finer details, also make sure you have the proper size rope, some guys think they are clever by going with skinnier rope so they can fit more in, this not only side jams into the spool reel resulting in extreme loss of power when pulling, it will also keep you from getting into the variable ratio change for optimum starting power...

                      Single file stacking is so very important - how much? it can easily mean DOUBLE the leverage ratio from first pull as compared to last extended effort....
                      Last edited by A.K. Boomer; 01-27-2022, 10:13 AM.

                      Comment


                      • #12
                        Is the saw hard to start or is it physically hard to crank over with the rope?

                        It always seems to me you need to figure out the proper “procedure” to get saws started. I have an old Echo, if you would try and start it like common sense would tell you good luck, do the “procedure” and fires right up.

                        I don’t think the handle is meant to try and get your boot though when starting, I always thought that the bottom of the handle was wide so you could get the side and ball of your foot on it going in-line with the bar.

                        Comment


                        • #13
                          Originally posted by oxford View Post
                          I don’t think the handle is meant to try and get your boot though when starting, I always thought that the bottom of the handle was wide so you could get the side and ball of your foot on it going in-line with the bar.
                          I did not notice that the handle on the new Stihl was wide in the right side but you are absolutely correct. My old ProMac handle is fat on both sides and I never thought to use the right side. But that will work just fine. Once I get the chain fixed and back on.

                          One thing with the Stihl - it appears if the chain comes off, the sprocket dings it up enough that you need a file to get it back on the bar. Never had that issue with the ProMac.



                          You may only view thumbnails in this gallery. This gallery has 3 photos.
                          Last edited by flathead4; 01-27-2022, 12:04 PM.
                          Tom - Spotsylvania, VA

                          Comment


                          • #14
                            I dont have a compression release on my 066 and sometimes it pulls hard but I didnt think an 026 could pull that hard. My 025 thinks I am trying to wring its neck after I run the 066 first.

                            Comment


                            • #15
                              When we first tried to crank the saw, the air cleaner was totally clogged, so some of the difficulty might have been due to that. Since that time, I was mostly concerned with removing the covers and figuring out the compression release issue. It's also possible that there could have been rust or debris in the cylinder, and the subsequent efforts to crank it may have loosened it up a bit. I seem to remember that it was hard to crank with the spark plug removed, but now it turns over freely except for the expected resistance from the magneto. Thanks for the advice. I'll report back later. I don't have a really good place to work on the saw and the next few days will be arctic cold and some heavy snow and high winds, but after that we'll have a nice warm-up.
                              http://pauleschoen.com/pix/PM08_P76_P54.png
                              Paul , P S Technology, Inc. and MrTibbs
                              USA Maryland 21030

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