Stihl 021, 023, 025 Gas & Oil Leak Repair

This video is of a repair on a Stihl 021. It was leaking oil and gas. I replaced the necessary parts, oil line, O-ring, and tank vent. I also replaced the chain sprocket, as it was very worn.
Hose connector # STI 1123 640 2901
Hose # STI 1123 647 9400

[@kathleenlairscey5934]

I am a grandmother learning to maintain my Stihl chainsaw, it is getting old but runs great. It's been leaking gas and don't want to get blown up. Very well done education.

[@davidspence7385]

Thanks for the tutorial! I’ve had the same oil leak for 20 years. Time to fix it now.

[@johnclarke6647]

Removing the E clip from the crank on a Stihl saw. This is the best way Inhave found to keep from loosing it. I take a blue paper shop towel and kind of fluff it up and put it under the saw and the E clip. I rotate the E clip until it is pointed downward towards the blue towel. II pry it off the crank with my small carb adjustment screwdriver. I then take a hammer and tap the partially removed E clip off the crank by putting the same screwdriver in the clip and tapping it off the crank. I don’t even try to restrain the E clip with my fingers because it will fly into the blue paper towel where it can be recovered. I use the edge of blade of the screw driver in the E clip and tap it until it flies off into the blue towel.

[@johnclarke6647]

Save the old plastic manifold, after you retrieve it from the floor. You may need it in the future. Pack the white lithium grease into the sprocket bearing, good. Clean off the crank before you put it back on. If I had gone that far on the clutch side, I would pull the clutch and clean under it real good with compressed air and lubricate the worm gear and check the oil pump at the same time.

[@terryhuston9011]

Great video! I have the same problem. Thanks

[@johnclarke6647]

I recently picked up an 021 off EBay - it was missing a few parts - the air direction plate behind the muffler, a muffler gasket and the cover washer over the worm gear. I have them, now and will put them on. The reason it would not run was two fold - a leaking fuel line and disconnected impulse line. Mi replaced the carb with a dual jet AM carb. I do not like single jet carbs. Anytime you acquire something with no history it is best to go through it with a fine toothed comb and replace all missing parts. If in doubt consult an IPL to make sure. A lot of jackasses remove any part they don’t know how it goes on or is difficult to install a certain part, correctly. I do things by the book - First Sergeants are that way. Not much on a Stihl saw escapes me these days since I have 20 of them. I have completely cleaned up the 021 - now to get it back together with a lot of new parts.

[@century80]

Great video! Very helpful. Thanks for sharing your expertise!

[@techguy9023]

Very helpful. Thanks

[@jacoblang2712]

My 021 clutch bearing went out on the old owner and still worked and he didn't know ..well I bought it for150$ and took it home and found out it wouldn t oil the chain..MAN ! Was I jacked..but tore into it .put new oil pump and hoses..on and jb welded the case..fix the clutch bearing .new 16 inch bar and chain..230$ later awesome saw

[@tp8030]

Thank you

[@johnclarke6647]

I would like to see how you replace the impulse line on an 021.

[@jacoblang2712]

O21 is my faverit little saw..but my air cleaner is just a screen..should I have felt gona over that too?

[@johnclarke6647]

Maybe you can help me with a problem that I have with my 021. I had to replace the crank because the rod bearings were shot. I think that I ended up with a Stihl 210 crank. I also had to replace the cases because the original cases had been turned into a crispy critter on the PTO side by its previous owner. Everything went back together fine but if I put the cover washer on top of the worm gear the worm gear will not turn after the clutch is tightened down.there is a clip on the crank to probably keep the wor gear from going to deep. I think the clutch pushes the worm gear down so far that it binds up the worm gear. I am thinking about removing this clip because that would give it more clearance. Your thoughts.

[@mommyoftwoboys123]

Your videos have been very helpful. We need to replace an Impulse Line on our Stihl O25. We can’t seem to find any videos. Would videos of other models be the same. Perhaps the O24?

[@aeridyne]

Part numbers on the oil line plastic and rubber would be great. Every time I call the closest dealer they have the worst time looking up parts if I don't tell the the exact numbers to start with. Great video though, thanks.

[@Scotcho64]

They were in comments below: Hose connector # STI 1123 640 2901 Hose # STI 1123 647 9400

[@aeridyne]

@@Scotcho64 Oh I didn't see that, looked through the manuals already and figured it out but thanks for replying!

[@Cocodrankspearfishing]

What is the plug that goes in under the muffler called? Can’t find one anywhere for my 025 it’s spewing oil!

[@redneckworksllc9111]

Do you have the part numbers for what you replaced? I'm having the same issue with the leak but a hard time finding the part numbers

[@Scotcho64]

I will see if I can find them.

[@Scotcho64]

Hose connector # STI 1123 640 2901 Hose # STI 1123 647 9400

[@redneckworksllc9111]

Awesome thank you for taking the time to look them!

[@zulfadhlipuasa8917]

Hi, is it the piston n block for stihl 023 same with 025?

[@Scotcho64]

I am not sure. But according to the manuals, the 023 engine displacement is 40.2 cm while the 025 is 44.3 ccm. The bore for the 023 is 40 mm or 42 mm while the 025 is 42 mm. Hope that helps a little.

[@98fishingfool]

Do you have any blown up saws around you want to get rid of

[@Scotcho64]

Sorry I dont. Typically when I find them I rebuild them myself.

[@123jonish]

I am trying to change the fuel line and impulse line. I am not seeing the impulse line on the older 021. I assume it has one. Can you direct me?

[@Scotcho64]

You might find some help here. You can select difference pages until you find what you're looking for: www.diyspareparts.com/parts/stihl/diagrams/023/c80270f4-5e37-421f-aad9/

[@damienwemmerslager853]

Did it have one

[@dufferat]

Too bad you don't show how to gain access to the oil pump!