Stihl 021 teardown, with pics, and questions...

[wrooster]

So I have this old (12-15 yrs) 021 that has served as an occasional firewood saw -- the trouble started when I loaned it out. Fast forward 2 years, I have the saw back and, I quote, "it doesn't start". I love my in-laws, I really do.

In the tank was ancient 50:1 mix, and the bar and chain, although turned over once in a while, are both in bad shape. The amount of caked-on dirt and grime was interesting.

I have decided to make a small project out of this saw and put it back in running order.

So far I have found a lot of wear and tear; apparently the reason it does not start is either the cracks in the fuel line and/or the cracks in the impulse line.

I am going to purchase the following at the parts counter:
- fuel filter
- fuel line
- impulse line
- Walbro carb rebuild kit (Ebay?)
- spark plug
- sprocket (OEM)
- bar/chain combo (Bailey's inexpensive Arborist setup)

The question now is "how far do I go in?"

I compression-tested it (obviously cold) and it came up to 125psi before the flywheel un-keyed itself. (Aside, I tried gently for 5 minutes to get the flywheel off without a puller, but after about 8-10 yanks on the starter cable it came right off). I will put the flywheel back in place with the nut and see if a little more compression is there.

Through the exhaust and inlet ports there is no visible scuffing or damage to the piston.

Based on the above, I'm inclined not to take the jug off and go all the way down to the guts.

Finally, what's the best way to clean the motor assembly itself of all of the accumulated grease, dirt, grime, and other debris?

Ideas? Opinions? Suggestions?

Thanks,
Jim / Wrooster

 

[Rookie1]

Wow! Where to begin. Get the flywheel back on and verify compression. If its that low I think thats why it wont start. Sprocket looks wasted. Crud is no biggie.You may want to just ebay the parts and make some money with it. Im sure you dont want to hear that but with low compression its going to take alot more time.

 

[wrooster]

but with low compression

Do you/anyone know what a 021 should push in PSI? I was thinking 140-ish?

Regards,
Jim / Wrooster

 

[wrooster]

1) I re-ran the compression test and it gives 135PSI.

2) Question regarding the chain sprocket -- the 021 OEM setup is a Picco type, and the OEM sprocket says "1123/05 Picco z6" on it. From Bailey's website, it appears that I could get a setup (sprocket/bar/chain) to match the OEM setup Picco 0.375" x 0.050", OR i could get a 0.325" x 0.063". I'm inclined to stay with the narrower kerf on an 021, and match the OEM setup. Thoughts?

Thanks
Jim / Wrooster

 

[HimWill]

When you dumped the old gas ,did you start it up with fresh gas?If so,how was it running?

 

[ironman_gq]

I would at a minimum put new rings on it. I would think it would be closer to 150/160psi. Use Brakleen and an air compressor to remove the crud, replace the lines and make sure the oiler works. It shouldnt be too expensive but it will take time and patience

 

[wrooster]

When you dumped the old gas ,did you start it up with fresh gas?

No. When I did a quick inspection and saw the cracks in the fuel line I started in on disassembly.

 

[wrooster]

I would at a minimum put new rings on it.

http://www.baileysonline.com/itemdetail.asp?item=PKS%20021

The whole piston/ring kit is $29. If I have it torn down to the guts and the cylinder walls look OK, I probably should go the whole way -- what do you think?

 

[HimWill]

Does this engine have the un-caged lower rod bearings?If so,be aware that they are prone to "skedaddle" when you move the rod too far left or right on the crank.Keep the rod centered and wrap something around each side to limit side to side movement.I use a strip of an old T-shirt wrapped and tied to keep the rod centered.
I have used the Baileys piston and ring combo that you mentioned,no problems.Ring installation is easy,no compressor is required because the cylinder has a tapered lead in.
For cleanup,remove the coil and use Lake's formula of 25% Purple cleaner sprayed on,let sit for a while and then hose it off with a garden hose.Repeat as needed until clean.Let it air dry,on blow dry with compressed air if available.

 

[wrooster]

and I still need the impulse line from the dealer (can't find one on Bailey's website)...

Possibly: :crazy1:

Jim / Wrooster

 

[HimWill]

Just about identical to what I ordered,14" bar and chain on this one.Cutting little devil now.I also ordered a set of rings as well as the piston/ring combne of them(bought 3 in a box and made 2 ) had a good piston,just needed rings.The other needed piston and rings,crank bearings and seals due to clutch-side bearing spacer coming apart and working its way out through the engine.If the impulse line looks good,it probably doesn't need replacing yet.
Neither carb needed a rebuild,just lucky I guess,but I would get it back together and running before I worried about the carb

 

[wrooster]

Just about identical to what I ordered,14" bar and chain on this one.

Actually I don't know how I ended up with the 16" setup in the cart, I thought I put the 14" in there. Tonight when I finalize the order I'll make the decision one way or the other. IMHO swinging a 16" bar/chain is a lot for an 021.

If the impulse line looks good,it probably doesn't need replacing yet.

The impulse line definitely has some cracks in it.

Neither carb needed a rebuild,just lucky I guess,but I would get it back together and running before I worried about the carb

That's a good idea. On the other hand the carb has sat for at least a year and change with old gas in it. I probably need to at least spray down the internals with carb cleaner.

Thanks for your info above.

Jim / Wrooster

 

[Fish]

So you need an impulse line, sprocket, and flywheel...

Would you like fries with that?

 

[Fish]

Well 2 out of 3........

 

[wrooster]

So you need an impulse line, sprocket, and flywheel...

Flywheel is OK, sprocket is hosed bad (see pic above), but yes I need a new impulse line.

Jim / Wrooster

 

[Fish]

How about a fuel line, carb? I only have the 6 toothed sprocket in Picco 3/8 l.p.

 

[wrooster]

How about a fuel line, carb? I only have the 6 toothed sprocket in Picco 3/8 l.p.

I haven't put an order in anyplace yet, and I'm still looking for new seals. The Bailey's list I posted previously is still in "DRAFT" form -- I want to do a little more detective work this evening to see if there is anything else I need before placing an order.

PS
I still have two pretty good condition OEM chains for this saw so I am reluctant to change the drive setup. I don't know if the 6T Picco sprocket is available in an equivalent rim drive. Ideas?

Thanks
Jim / Wrooster

 

[wrooster]

Can anyone think of any 021/023/025 common wear or breakage items that I should look at? I need to get an order in an don't want to have to do it again in 72 hours...

Thanks
Jim / Wrooster

 

[Rookie1]

Ive had a 021 for a while and just put an 023L together. I think impulse and fuel line and maybe one screw carb is a bit of a drag. They arent pro saws but I think for homeowner not loaning it out it will do well with what your doing.

 

[windthrown]

Your compression tester has a LONG auto hose on it, and you are probably going to read low using that (unless you have a release valve down by the threaded end of the tester). There have been a lot of chat about that on several threads on AS over the years. Your engine may be better than you think.

May want new crank seals while you are in there. Sprocket is beyond shot. Flywheel with no key is shot (or re-key, or get one on Ebay; I just sold a 1123 flywheel there for $8). Definately get the picco 3/8 low profile B&C. .325 is too fat a kerf and a 210 will not drive that. I run picco on my new 250/025 hybrid (which I tore down and put a new tank on just yesterday). I have .325 bars and chains that I never use on it. Overall with shipping, I would say that $100+ is a lot to put into a 210.

Oh, to answer your original question, you are already all the way into that thing. To get the flywheel off a 1123 saw, I use a small puller. The way I do it is loosen the engine and that gives you more room to get behind the flywheel with a puller.