Stihl 026 non-start mystery

[Belegedhel]

So this one has me stumped (no pun intended). I have just inherited a Stihl 026 saw. Brother in-law says it was running fine one day, and the very next day, it woudn't start, and hasn't started since. It has compression, and it has spark. The choke on the air filter is not stuck, and working properly. I can pull on the starter rope for an hour and won't get so much as a single "pop." Even if I try using starting fluid, even to the point of spraying it directly in the cylinder through the spark plug hole, I don't get a single pop out of it. I tried a different sparkplug from another working saw, and still no change. I even went so far as to remove the flywheel, thinking maybe the key had sheared, and that the timing might be off, but all looked fine there as well.

Any other ideas?

 

[Armbru84]

Take the air filter off and just spray mix into the carb. See if you can get it to pop.

Piston etc look fine? Make sure the jets are open on the carb?

 

[dmb2613]

they do flood ez

 

[Belegedhel]

Yep, I've tried to spray the starting fluid directly into the carb with the air filter both on and off, with the throttle wide open. Looking at the piston from the exhaust port, I don't see any issues.

 

[Armbru84]

Hold the throttle wide open and try starting it next time. Non choked.

 

[Belegedhel]

The majority of my attempts to get it to at least respond to the starting fluid have been with the throttle wide open. No luck...

 

[HarleyT]

Probably just flooded real bad.
Take off the bar and chain for now.
Dump out all of the old fuel and pull the plug, and pull the rope a few dozen times and let the saw sit in the sun for a while.
Put in a new plug, and do not add fuel, but pull the rope a bit while holding the trigger down, see if it will hit.

After you are certain that it is totally dried out, then retry the squirt of fuel test. It should start and run until the squirt is burned off.

 

[merc_man]

Did you check for spark?

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[Tin-knocker]

Did you check for spark?

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He said it did have spark. What does the plug look like after you yank the starter a couple times? Dry? Wet?

 

[Belegedhel]

Yes, it sparks just fine. I probably need to follow the advice from above and completely empty the fuel system and clear the carb so that I can be sure that I am not flooding it. It does have some old gas in the tank, and the plug has ended up wet a time or two when I have opened it up. I'm just surprised that it would be capable of flooding before it would ignite the starting fluid, especially with no chocking going on and the throttle butterfly wide open.

 

[JimM]

Yes, it sparks just fine. I probably need to follow the advice from above and completely empty the fuel system and clear the carb so that I can be sure that I am not flooding it. It does have some old gas in the tank, and the plug has ended up wet a time or two when I have opened it up. I'm just surprised that it would be capable of flooding before it would ignite the starting fluid, especially with no chocking going on and the throttle butterfly wide open.

How old is ‘old gas’? Get rid of it.

 

[HarleyT]

Old gas doesn't burn too well any way.

Dry it out real good, easy on the starting fluid.
I blew up a Ryobi trimmer once with it, blew the cylinder right in pieces....

I enjoyed it....

 

[JimM]

Old gas doesn't burn too well any way.

Dry it out real good, easy on the starting fluid.
I blew up a Ryobi trimmer once with it, blew the cylinder right in pieces....

I enjoyed it....

If I had a dime for every time someone asked me why their weed eater /chainsaw, didn’t run right after setting with last seasons fuel, and I said dump it and use fresh mix, and it worked, I would probably have 5 or 6 dimes.

 

[HarleyT]

When I worked on stuff at our house/farm, I would just take the thing over to our burn pile, and dump out the fuel on some trash. And then step back and throw a match.
The old fuel usually would start off like kerosene.

 

[dmb2613]

If you follow Harleys advice I am betting it will run , try with no either they are ez to flood as I said

 

[rupedoggy]

You say good compression. How many PSI?
You pulled on it 100 times? Com'on stop that.
Stop the starter fluid also.

 

[merc_man]

Any luck getting the 026 running?

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[Belegedhel]

Here's the update: Fuel is drained and discarded, carb is dry, no fuel in the system. I put a few drops of oil in the cylinder to ensure that I am not causing damage by cranking it with a dry cylinder. Have made a few attempts to get it to pop using a reasonable squirt of starting fluid with the throttle wide open. Not a pop. When I say that it has good compression, I mean relative to my trusty 025, which will start and run for several seconds on a shot of starting fluid with a dry tank. I realize that the use of starting fluid is not a recommended practice, I am just assuming that the carb is likely to be gunked up with old funky fuel, so am trying to take that out of the equation.

 

[captain dangers]

Here's the update: Fuel is drained and discarded, carb is dry, no fuel in the system. I put a few drops of oil in the cylinder to ensure that I am not causing damage by cranking it with a dry cylinder. Have made a few attempts to get it to pop using a reasonable squirt of starting fluid with the throttle wide open. Not a pop. When I say that it has good compression, I mean relative to my trusty 025, which will start and run for several seconds on a shot of starting fluid with a dry tank. I realize that the use of starting fluid is not a recommended practice, I am just assuming that the carb is likely to be gunked up with old funky fuel, so am trying to take that out of the equation.

just a thought? try it with the exhaust removed ? and whilst its removed check for scoring on the piston, this series of stihl are common for sucking in carbon, from build up on the exhaust port, due to the restricted exhaust. the restriction can also effect starting on old saws to with some millage. if it starts o.k with muffler off? muffler mod it ;o) if it needs a new piston, muffler mod at the same time to stop the build up of carbon ;o) CD

 

[Belegedhel]

The muffler on my saw has something of an outside "door", that can be removed with a couple of screws. Once that is off, I can see the (empty) interior of the muffler and the exhaust port. No noticeable buildup there, and I can see the piston moving up and down. There might be some scoring on the piston, but as mentioned above, I still get at least as much compression as I have in my 025. Interesting side note, when I added the couple of drops of oil to the cylinder, the compression went up dramatically for the first few pulls, much more than I would have expected.