Stihl 026 PRO

[panorain]

Hi, I have a Stihl 026 PRO saw bought new by myself. I am looking for a service manual and a parts list if possible (I have the user manual). These are important as my starting point. The saw died on me suddenly during a cut when running well. The saw has spark and fuel and 130 PSI of compression when pulled over 3 times. The saw will not start so I am thinking that there is a possible piston/ring issue. I believe I should pull off the head next.

 

-Greatest Hopes

[spudulike]

What is the compression if you keep pulling it over as 130 is a bit low. 150+ is normal on these machines with 175 being pretty good.

Have you popped off the muffler front and taken a look at the piston? When a machine dies like this, electrical or seizure are the common issues.

[spudulike]

024, 026, MS240, MS260.pdf 024 026.pdf

[panorain]

I thank you for your reply to my message, I did not see a comment in my email. Compression was low at 90 psi, pulling over multiple times. I removed the muffler front. I saw scuffing and some lines on the piston. Then I proceeded to remove the head. The piston, rings and head had *failed*. The Stihl dealer wanted 248.00 U.S.D for a head kit. I bought this kit >

Big Bore Cylinder Piston Kit For Stihl 026 MS260 026PRO Chainsaw 44.7mm -Nikasil

WWW.EBAY.COM

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Feature: Nikasil Plated. 1 x Cylinder Piston Kit, 1 x Gasket Set (3pcs), 1 x Oil Seal Set (2pcs), 1 x Needle Bearing, 1 x Spark...

from ebay. I did not use the kits Crankseals or the new bearing (not as long as OEM). I did use the piston, piston pin, clips and head from the kit. I put some wd-40 on the original crank and rod bearings. It was a bit difficult to complete this but I got everything back together correctly. The saw starts and runs now.

 

1. Do I need to break the new piston in somehow?

2. What caused the failure? I always have mixed the gas correctly.

3. Recently been using Penzoil 2 stroke marine mixing oil with the saws fuel. Is this ok? I have a 2-stroke 4 wheeler I use this oil with also.

4. What other information is good that I know?

 

@spudulike, I thank you for your help with the parts manual and service manual.

Edited July 21 by panorain
Wording

[Stubby]

23 minutes ago, panorain said:

I thank you for your reply to my message, I did not see a comment in my email. Compression was low at 90 psi, pulling over multiple times. I removed the muffler front. I saw scuffing and some lines on the piston. Then I proceeded to remove the head. The piston, rings and head had *failed*. The Stihl dealer wanted 248.00 U.S.D for a head kit. I bought this kit >

Big Bore Cylinder Piston Kit For Stihl 026 MS260 026PRO Chainsaw 44.7mm -Nikasil

WWW.EBAY.COM

---

Feature: Nikasil Plated. 1 x Cylinder Piston Kit, 1 x Gasket Set (3pcs), 1 x Oil Seal Set (2pcs), 1 x Needle Bearing, 1 x Spark...

from ebay. I did not use the kits Crankseals or the new bearing (not as long as OEM). I did use the piston, piston pin, clips and head from the kit. I put some wd-40 on the original crank and rod bearings. It was a bit difficult to complete this but I got everything back together correctly. The saw starts and runs now.

 

1. Do I need to break the new piston in somehow?

2. What caused the failure? I always have mixed the gas correctly.

3. Recently been using Penzoil 2 stroke marine mixing oil with the saws fuel. Is this ok? I have a 2-stroke 4 wheeler I use this oil with also.

4. What other information is good that I know?

 

@spudulike, I thank you for your help with the parts manual and service manual.

Marine 2t oil is a no no on land based kit .  It will over heat . Also it seems you have not found the reason for the failure . If it was an air leak and you have not rectified it you will be doing this all over again . The failure could be down to you using marine 2t oil .  .

Edited July 21 by Stubby

[pleasant]

Agree with above...never use marine 2-stroke in non marine applications. Why, just why when there's a plethora of the proper stuff around?

[spudulike]

As above and running in...lots of flat out but SHORT periods so excessive heat isn't built up so small rings/ cuts but always use the saw flat out and avoid long drawn out cuts for the first couple of hours use.