026 arguing with me.

[DERaffle]

Hello all, I have spent alot of time on this site but this is my first post for help.

Stihl 026 issues


Okay, so here’s my story. I have been wanting to get a Stihl 026 for a while now. I have an old 031 and an 011 and wanted something newer. An 026 PRO showed up not too far away at an ok price so the dog and I got in the truck and went to see it. The dude said it would run but started hard and he didn’t want to mess with it any longer. Didn’t look overly beat up and had a new Stihl 18” B&C. after a bit of effort, I was able to start and run it and it seemed to have compression. I of course assumed he worked on it a while before I got there. I offered him a good bit less and he (probably too quickly) agreed. So we took my new saw and went home. BTW, he is definitely NOT a Stihl guy... Poulan i think.

At home, it was hard to start but it did start. He put an aftermarket carb on it but gave me the old (WT403A with no “H” adjustment) so I cleaned both in the ultrasonic cleaner and put the old carb back in. With some amount of tinkering I got it running, hard start and rough but running. I put in a new plug I had for my 031 and it really seemed to help. Started easier and ran. I actually cut some wood but it sputtered a bit at WOT, something just didn’t seem right. I was able to get it idling well but still didn’t seem happy when opened up so I put in a new impulse and fuel filter & pick-up, all OEM. They all went in without issue. This is where things got interesting. Now the saw does not seem like it wants to start. It will occasionally start when I pour fuel into the filter or carb and will then run and idle, actually sounds good, until I hit the kill switch. I had already found and ordered a WT194 but it didn’t seem to make a difference.

I picked up a Harbor Freight compression tester and it showed around 40 lbs but not sure I trust it. When I do the “pull start hang” test, it stops 10” down and just hangs but the compression probably is low. Probably the problem all along. I did pull the decomp valve and cleaned it, it seems fine.

I pulled the muffler and the piston & cylinder don’t seem to be damaged. I didn’t change the intake boot, looked a bit daunting for an amateur. I am now wondering if I now have a parts saw for the next 026 I pick up that is already running well.

I plan to pull the cylinder, I had to pick up a long thin T27 for the head bolt as mine was too thick.

I really didn’t intend to get a "project" but I can’t say that I’m not enjoying the tinkering. I am by no measure a small engine mechanic but I can follow a YouTube video and with the best of them! Lol

I really would like to get this thing running but not sure what to do next. Would replacing the rings be worthwhile or should I stop putting good money (and time) to bad? It seems like I'm missing something other than the $'s I've already spent.


Any advice would be greatly appreciated.


Thanks in advance,


David

 

[JP56]

You could have some pinholes or cracks in the intake boot allowing for some vac leaks, which can cause some starting & idling problems, and it wouldn't hurt to check the coil to flywheel gap adjustment. Those could be problematic with starting & running, but your compression does seem very low. Your problem could be related to all 3 factors.

I am a novice to all this myself, having only worked on car & truck engines most of my life until about a year ago, but my comments are all based on what I went through and found with my MS290, and also with my BR380 back pack blower, which had the coil gap improperly set straight from the factory. Once I decided to check the coil gap & found it was not right, I set it to spec & that thing now starts on 1 or 2 pulls every single time, no matter how long it sits for.

Also, do yourself a big favor & don't even bother with ANY after market parts for the STIHLs. You can find some good deals on the net and at both Ebay & Amazon on a lot of parts. There are a lot of New old stock parts out there. Good luck.

 

[Mad Professor]

If it starts when primed through carb you might have a choke problem. It's inside the air filter.

The throttle linkage that closes/opens choke can get worn, or the choke can not be closing.

Pull the two halves of the air filter apart and check it (a good time to give it a good cleaning), there is a torsion spring in there.

Also some AM air filters are POS and chokes don't work. Look for stihl part #s to see if it's OEM.

If P/C look good I'd not trust the Chi-Com comp tester. See what it reads on your other saws/blower. If they have better compression I'd plug/or replace the decomp before pulling the P/C.

You don't really need a decomp on a 026, unless you have arm/shoulder problems, or the wife/GF runs the saw.

 

[DERaffle]

You could have some pinholes or cracks in the intake boot allowing for some vac leaks, which can cause some starting & idling problems, and it wouldn't hurt to check the coil to flywheel gap adjustment. Those could be problematic with starting & running, but your compression does seem very low. Your problem could be related to all 3 factors.

I am a novice to all this myself, having only worked on car & truck engines most of my life until about a year ago, but my comments are all based on what I went through and found with my MS290, and also with my BR380 back pack blower, which had the coil gap improperly set straight from the factory. Once I decided to check the coil gap & found it was not right, I set it to spec & that thing now starts on 1 or 2 pulls every single time, no matter how long it sits for.

Also, do yourself a big favor & don't even bother with ANY after market parts for the STIHLs. You can find some good deals on the net and at both Ebay & Amazon on a lot of parts. There are a lot of New old stock parts out there. Good luck.

I did set the ignition module. I use a business card. Didn’t seem to make a difference. I may change the intake boot, just hate to keep throwing money at it.
Thanks for the response!

 

[DERaffle]

If it starts when primed through carb you might have a choke problem. It's inside the air filter.

The throttle linkage that closes/opens choke can get worn, or the choke can not be closing.

Pull the two halves of the air filter apart and check it (a good time to give it a good cleaning), there is a torsion spring in there.

Also some AM air filters are POS and chokes don't work. Look for stihl part #s to see if it's OEM.

If P/C look good I'd not trust the Chi-Com comp tester. See what it reads on your other saws/blower. If they have better compression I'd plug/or replace the decomp before pulling the P/C.

You don't really need a decomp on a 026, unless you have arm/shoulder problems, or the wife/GF runs the saw.

It doesn’t always start when primed and the choke does work, pretty sure it’s OEM.
Great idea on checking tester on other equipment. I will do that directly.

Wife doesn’t use the saw and I I had a gf the saw would be the least of my problems! Lol

Thanks for the reply!

 

[pioneerguy600]

Welcome to the site David. It depends on how much you already have spent on this 026 to say if you should keep going deeper. For me I don`t consider cost but I know its important to most. There are a few members on here that know the 026`s very well and we can get you through anything they throw at you. Compression needs to be over 120 lbs for an 026 to work even reasonably well. If the piston is not scored the rings may just be worn out causing low compression.

 

[Mad Professor]

Wife doesn’t use the saw and I I had a gf the saw would be the least of my problems! Lol

Some girls in the woods work out fine......

 

[irhunter]

The 026 is a great saw. But, not everyone is destined to enjoy owning old saws.

I would start by asking around, and finding a buddy with a compression tester...confirm your HFT numbers.

Roy

 

[DERaffle]

The 026 is a great saw. But, not everyone is destined to enjoy owning old saws.

I would start by asking around, and finding a buddy with a compression tester...confirm your HFT numbers.

Roy

For a little background, I have 14 old Gravelys in the shed all running, at least they were when I put them away for the winter so I do love the challenge of resurrecting things. I did check the tester on my very low hour 7 hp Honda snowblower and it read 90+ which is probably about right for that engine. I still may look to borrow one just to be sure.
Thanks for the input!

 

[irhunter]

That makes it sound like you have low compression. I would squirt some soapy water on the decomp valve to see it it's leaking.

Caber makes nice rings which are very reasonably priced.

 

[DERaffle]

Welcome to the site David. It depends on how much you already have spent on this 026 to say if you should keep going deeper. For me I don`t consider cost but I know its important to most. There are a few members on here that know the 026`s very well and we can get you through anything they throw at you. Compression needs to be over 120 lbs for an 026 to work even reasonably well. If the piston is not scored the rings may just be worn out causing low compression

That makes it sound like you have low compression. I would squirt some soapy water on the decomp valve to see it it's leaking.

Caber makes nice rings which are very reasonably priced.

I actually did do the soapy water test hoping against hope that that would be the problem but no bubbles. Valve looks to be good.
So the caber rings are good? I wonder if I should replace the piston as well?
Thanks for the reply!

 

[pioneerguy600]

A new Meteor piston kit comes with new Caber rings, its a no brainer for me and do this on every teardown, usually use OEM parts for my own stuff but some want to save a few dollars.

 

[Wood Doctor]

"I picked up a Harbor Freight compression tester and it showed around 40 lbs but not sure I trust it."
----------------------------
That compression tester might be junk. As Pioneerguy600 said, "120 is bare bones."
OR
The 026 PRO has a decomp valve. Perhaps it was pushed in (open) when you ran the compression test. Please check that compression again. Be sure the decomp is pulled out.

 

[pioneerguy600]

I have not seen one register below 90 lbs with an open decomp but anything could be possible, maybe if the compression is already very low the reading with an open decomp would be in the 40 lb range.

 

[DERaffle]

I have not seen one register below 90 lbs with an open decomp but anything could be possible, maybe if the compression is already very low the reading with an open decomp would be in the 40 lb range.

I’m sure the decomp was closed, I even tested it right after the engine ran. I did also test the valve with soapy water for a leak and no bubbles. I am going to try to find someone to borrow a tester from to be sure.
Thanks for the reply!

 

[gmctyphoon]

He did say that this saw will run. Just not well.

That’s not going to happen with 40lbs of compression..

OP, you really need to do a vacuum test on the saw to see if it has a leak. Sure sounds like it does.
Also when looking into the cylinder from the exhaust port make sure you rotate the piston to also check the intake side of the cylinder.

 

[John Lyngdal]

I've rebuilt a bunch of 024/026 saws and they're super easy to work on as long as you have a T27 long driver and 8mm spin tight driver.
If it fires and runs with fuel down the carburetor throat then dies out, the compression is still marginal to good, but something in the fuel delivery system is the issue.
This includes fuel lines, crankshaft seals, carburetor cylinder boot, plugged fuel filters, leaking fuel lines, an ethanol damaged metering diaphragm, or one or both debris clogged jets.
If you have good spark and you can't get the saw to run briefly with fuel down the carburetor throat chances are the compression is the issue.
If the fuel down the throat starts the engine and it continues to run and revs then stumbles open the High jet ( one closest to the airfilter) a 1/4 turn and repeat.
If it still doesn't run, run the adjustments all the way in then back out to the original position and try starting it again.
If it still doesn't run back out the High jet another 1/4 turn and try to start it again.
If it doesn't run properly pull the carburetor and check the fuel filter screen and metering diaphragm.
If those look good, swap in a different carburetor.
If that doesn't work check the fuel line, fuel filter, impulse line, and carburetor cylinder boot for defects.
The last easy thing do check the torque on the mounting bolts and tighten as needed, if those are normal pull the cylinder and check the piston and cylinder bore for scoring, and also check is the cylinder gasket.
If all these look good, time do a vacuum test or just replace the crank shaft seals.

 

[drf255]

You really do need to vac test to know what the deal is. But a vac leak, unless massive, is gonna cause idle issues and not running issues (in general).

The intake boots on the saws are tough as nails. Never seen one torn, but if the AV mounts are bad, it’s possible.

Personally, I’d toss the 194 back on, set the screws to 1/1, and fire the saw with some fuel down the carb bore. Then run with the AF cover slipped on and no air filter.

Also, check that your spark screen isn’t gummed up with carbon. Clean with a propane torch if it is.

 

[rd35]

Hey DERaffle. If you have not tried this yet.....here's something that might solve this mystery.....with the saw stone cold, like letting it sit over night, try to start it like normal with the choke on. If it wont hit at all then use your thumb to press down hard on the ignition/choke lever anc crank it while you do that. It'll probably start. If it does...you need to replace your air filter with a good oem new one because the choke flap is not shutting all the way when you choke it! My dad's 026 and my MS260 both had that same problem.

 

[DERaffle]

I've rebuilt a bunch of 024/026 saws and they're super easy to work on as long as you have a T27 long driver and 8mm spin tight driver.
If it fires and runs with fuel down the carburetor throat then dies out, the compression is still marginal to good, but something in the fuel delivery system is the issue.
This includes fuel lines, crankshaft seals, carburetor cylinder boot, plugged fuel filters, leaking fuel lines, an ethanol damaged metering diaphragm, or one or both debris clogged jets.
If you have good spark and you can't get the saw to run briefly with fuel down the carburetor throat chances are the compression is the issue.
If the fuel down the throat starts the engine and it continues to run and revs then stumbles open the High jet ( one closest to the airfilter) a 1/4 turn and repeat.
If it still doesn't run, run the adjustments all the way in then back out to the original position and try starting it again.
If it still doesn't run back out the High jet another 1/4 turn and try to start it again.
If it doesn't run properly pull the carburetor and check the fuel filter screen and metering diaphragm.
If those look good, swap in a different carburetor.
If that doesn't work check the fuel line, fuel filter, impulse line, and carburetor cylinder boot for defects.
The last easy thing do check the torque on the mounting bolts and tighten as needed, if those are normal pull the cylinder and check the piston and cylinder bore for scoring, and also check is the cylinder gasket.
If all these look good, time do a vacuum test or just replace the crank shaft seals.

I pulled the cylinder and it and the piston don’t look scored to me. Gasket looked fine too.
Not quite sure how to add pictures, didn’t know what size to make them.