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

[PStechPaul]

The kick start device in post #22 should be safe enough if the chain brake is engaged as recommended. I don't think hydro lock was a problem when first trying to crank it because IIRC there was no fuel in it when John tried it. He is stronger than I am but had a hard time. It was somewhat later that I took it to the Stihl dealer and he cranked it easily, but again, without fuel. We did add some fuel later and tried again, but I really didn't do much more with it. Since then I took the plug out again and cranked it a few times to verify it had spark, and it seemed easier to crank. It's supposed to warm up later this week so I'll be able to do some more on this chain saw.

My first chain saw was an old Homelite EZ with a blue metal case and a 20" bar. I bought it used around 1978. It had a compression release, and it started and ran well. But it was stolen along with other tools around 1990. I bought a Homelite XL and used it for quite a while until it stopped working.

I bought a Poulan Pro but never even tried it until maybe 5 years later. It worked pretty well for a couple years, and started reliably if I carefully followed the priming and adjustment procedure, but it got harder and harder. You might remember the thread I posted here a while ago. I had problems with the recoil spring. It might be worthwhile to get access to the crankshaft to use an electric drill to spin it up.

Eventually I gave up, and bought an Echo 56V battery powered saw, which has worked well, but isn't really powerful and rugged enough for some of the work. I also have a Remington 120 VAC electric saw, but the motor burned up while John was using it. Seems a lot of tools meet their death in his hands. And I have another smaller 14" "Wen Hornet" electric that still works OK. But the manual oiler is crappy.

About a year ago I bought a "Coocheer" saw on eBay, and it worked fine for a while, but then began having problems. Last I worked on it it seemed to have no spark, so probably the magneto, but it also had a problem with a bad connection from the wire to the cap. Another thing to tackle when it is warmer.

Hopefully this Stihl will prove a better investment - so far it has cost me nothing but time.

[flathead4]

The kick start device in post #22 should be safe enough if the chain brake is engaged as recommended.

I have never in my life started a chainsaw wearing shorts.

[oxford]

The kick start device in post #22 should be safe enough if the chain brake is engaged as recommended:

I don’t know what the intent is after the saw is running but I said it earlier, if you don’t have the arm strength to pull start the saw do you really have enough strength to operate it safely?

The foot starter is a solution to a problem you can’t solve with a foot starter.

[eKretz]

Unless my saws need the carbs cleaned, they all start with the normal procedure. Choke on, pull until the saw kicks over with an ignition (but doesn't start and keep running). Flip the choke off.

From here there are a couple different methods depending on the saw. For older saws, you generally have a throttle lock that needs to be set which holds the throttle in a partially open position, and you set that then pull start until it fires up and runs. Let it run at fast idle for a short while then pull the throttle trigger to disengage the throttle lock and put the saw to use.

For newer saws, many have that part throttle lock built in automatically, so that every time you put the choke on then turn it off, the saw is held at a partial throttle opening. Otherwise the starting procedure is the same.

If your saw won't start with little fuss with that procedure, you should investigate for air or fuel problems, most of the time when I have had that problem, it's been solved by either cleaning or rebuilding the carburetor.

[lynnl]

hmm. I got an ms291 a few years back. since the day I bought it, everytime I cold start (hasn't been run in 24+ hours). The first & second pull feel awefull & take a lot of strength. then I flip the switch up to start, almost always starts first pull, never more than 3. and if its hot, it starts half way through the first pull. Its always confused me, but I've never looked into it.

kinda sounds like this hydrolock you describe, doesn't it? is that normal on a new saw?

I've only had two new Stihl saws (I recently bought a new Husqvarna but only ran it a few times the first week or so), but doesn't sound normal, to me, for a new saw. Yeah, does sound kinda like a hydrolock issue, partially at least.

What I think I'd try: Next time, before ever pulling the cord, take the plug out and blow a few light blasts of shop air into the cylinder to clear out any residual fuel. Don't be in a hurry, allow time for any fuel to clear. Then put the plug back in and try starting. If the pulling feels more normal that would suggest a hydrolock issue. Won't solve the problem, but might at least shed some light on it.

One shop I took my MS211 to a few years back suggested there can be problems caused by the way the saw was shut down the last time used. Makes sense, could leave excess fuel in the cylinder. But I don't remember exactly how they said to do it. Should'a paid more attention, or written it down I guess.

[PStechPaul]

I just watched the video in my post #1,and I saw how easily the saw comes apart to access the cylinder and piston. He replaced both with good parts from an MS260 that had a compression release, and I can see where it would be a major job to retrofit with a compression release valve. I might see if the local small engine repair guy has a compatible cylinder and piston, but first I'll try to get this running.

[PStechPaul]

I took the saw to the local small engine guy and he said he would have to charge $30 just to properly evaluate the saw for repair, and because it is over 20 years old, it might be difficult (and expensive) to get parts, and would not be worth it. But at least he confirmed that the difficulty in cranking the saw was not normal, and might indicate a heavy build-up of carbon in the combustion chamber, probably from being run too rich. I said that when I got it, the air filter was heavily clogged, and he said that would do it. He also said that it might be possible to pour some carburetor cleaner into the cylinder and leave it there for a good while, which might loosen the carbon enough to get it out.

I think I will take it apart and remove the cylinder, which should confirm the diagnosis and allow for proper removal of the carbon, and it may also reveal other problems.

Maybe I'll try one of the solvents recommended here:
https://toolsarchive.com/best-solven...moving-carbon/

Also some discussion and testing, but for spark plugs:
https://www.physicsforums.com/thread...posits.878629/

[lakeside53]

Don't over-think this...

Pop of the cylinder (2 minutes)... then you can see the piston top and the interior of the cylinder. Use a long rotary wire brush and it will be clean in no time. Get new base gasket (couple $) and use an inch/lb torque wrench when putting it back together.

Don't put anything like carb cleaner into the cylinder unless it's off - you'll end up replacing crank seals and more.

Like most Stihl products of the same era, parts are available.

Personally, unless it's real bad, I'd just leave it alone and put on an Elasto-start pull handle (Stihl OEM). Run it with Stihl synthetic mix oil 50:1 and quality gas. It will clean up in no time. I've had hundreds of 026 and other saws apart... the 026 is dead simple, rock solid, and easy to work on.

[Jon Heron]

What Lakeside said.
You can also pop off the exhaust to get a look at the piston and cylinder for a quick diagnosis too.
Cheers,
Jon

[PStechPaul]

Got the cylinder off. Doesn't look too bad, but I guess even 1/32" or so might significantly increase compression.

[PStechPaul]

Looks like I can get a complete cylinder, piston, oil seals, etc., for only about $25. And it seems to include a compression release as well.

https://www.ebay.com/itm/362408309076

A carburetor kit is about $15:

https://www.ebay.com/itm/294453037929

https://www.ebay.com/itm/154480446197

I've placed an order for both. I guess now I need to tear it down a bit more so I can give everything a good cleaning. I can't believe these parts are available so cheaply. Hopefully they will be of decent quality. I am impressed about how easily this chainsaw comes apart.

[lynnl]

I don't know about that specific carburetor, but many of those carbs from Zama, Walbro, etc. (complete) can be had about as cheaply as the rebuild kits.

[oxford]

I don't know about that specific carburetor, but many of those carbs from Zama, Walbro, etc. (complete) can be had about as cheaply as the rebuild kits.

His links looks like it is the complete carb. I agree though, those small carbs are so cheap it isn’t worth screwing around with them.

[Willy]

............................
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.
...................................
.

This is why I mentioned back in post #2 of this thread to clean before disassembly.
Would have been much easier to clean the engine while it was still sealed without risking risking contamination to the crankcase.
Also remember proper assembly is a little more involved than taking things apart.

[lakeside53]

What Willy said ^^^

Not sure why you want a new cylinder etc. I can't see the piston, but the cylinder looks fine. The original is likely Mahle, and the one you buy will be cheap import with thin chrome internal coating.. Clean up the carbon, take of the rings and make sure here isn't carbon packed in the grooves (clean with the right tool). Check your piston also... there are two types - 44.7mm and 44, and 1.2mm and 1.5mm rings respectively.

I never used the compression release on the ms260's. Heck, I don't even us it on my 044 or MS660! Quick drop start they fire up on 3rd pull from cold, 1st when warm.