Stihl 026 headache

[JMCK]

I should add, after about 30 pulls, I popped off the muffler and the cylinder was full of fuel vapor so it seems it's getting ample fuel. Also ohmed out the coil and it is fine

Just got thinking, for once, after market fuel lines are usually quite thinner then oe stiff. They can kink and not appear to be? I remember the 026’s used two different fuel lines too. A more straight one and a more curvy one.

 

[Dieselcamino]

Pull the spark plug and put it back into the boot. You should be able to see spark when you pull the cord. If you have fuel vapour and no combustion, you might not be getting spark.

Great bright blue spark, and coil tests good, fuel puddling up in the exhaust, and ample compression. The saw just about holds its own weight by the pull cord

 

[Dieselcamino]

Just got thinking, for once, after market fuel lines are usually quite thinner then oe stiff. They can kink and not appear to be? I remember the 026’s used two different fuel lines too. A more straight one and a more curvy one.

It was a thought of mine, I ended up popping the oem fuel line back in as it was still in good shape, the aftermarket one was a bit too long

 

[jacrider]

Did that solve it?

If not, doesn’t it have to an issue with the timing? If you have fuel, spark and compression.

 

[BrettS]

Did that solve it?

If not, doesn’t it have to an issue with the timing? If you have fuel, spark and compression.

That's my thought, either that or air leak.

 

[Old2stroke]

Great bright blue spark, and coil tests good, fuel puddling up in the exhaust, and ample compression. The saw just about holds its own weight by the pull cord

I don't see anywhere in the posts that you have done a compression reading with a known good gauge, the "hang by it's cord" is NOT a very reliable test nor is the appearance of the piston, rings could be worn and the end gaps too big.

 

[Dieselcamino]

I don't see anywhere in the posts that you have done a compression reading with a known good gauge, the "hang by it's cord" is NOT a very reliable test nor is the appearance of the piston, rings could be worn and the end gaps too big.

I haven't yet done a true pressure test or compression test, the tools are en route. Judging visually by the condition inside and out didn't think I would need it, but I will use them again down the road

 

[bigbadbob]

Great bright blue spark, and coil tests good, fuel puddling up in the exhaust, and ample compression. The saw just about holds its own weight by the pull cord

Could it be flooded real bad??

 

[Dieselcamino]

Could it be flooded real bad??

Possible... But I only have the low jet 1 turn out from bottom, you would think it would still fire up on that

 

[bigbadbob]

Pull the plug turn saw muffler down pull you heart out,, and let it sit overnite,, hanging by the handle.
Some saws get flooded,, they need to be dried out good. No choke full throttle first start.
Go from there if it dont fire.
At this point it cant hurt,,,

 

[Dieselcamino]

Pull the plug turn saw muffler down pull you heart out,, and let it sit overnite,, hanging by the handle.
Some saws get flooded,, they need to be dried out good. No choke full throttle first start.
Go from there if it dont fire.
At this point it cant hurt,,,

Ill try it tomorrow! At this point it's a matter of winning or loosing

 

[John Lyngdal]

I'll offer another suggestion once you're sure the saw isn't flooded.
I would run both jets in until they seat, then pull it over a 6-8 times just to see if it "pops".
Then with the throttle depressed squirt a bit of fuel mix down the throat of the carburetor, then with the throttle depressed, try to start it and see if the saw "pops" after 6-8 pulls. If it doesn't "pop", add a little more fuel and give it another go.
If you can't get it to "pop" or briefly run, it's more likely a timing issue than a fuel delivery issue.

 

[a. palmer jr.]

I once had an 025 that everything seemed good, compression, spark, fuel, all okay but wouldn't hit a lick. Turns out it had the wrong flywheel (018) on it and the spark was at the wrong time. The only way I could tell was to read the part number on the parts. Previous owner thought the flywheels looked the same so they should interchange, they didn't...

 

[Okie294life]

Have you tried checking the flywheel gap to coil and spark? Could be flooded pull plug and turn upside down and crank a few times. Then leave it on idle to see if it will rip. Sounds to me like it has a leak somewhere it should run okay at about 1-1.5 or so turns out on the needles

 

[Okie294life]

The key could also be partially sheared off causing it to be out of time?

 

[Pioneer]

Check to see the leading magnet on the flywheel is a little past the coil in the direction of rotation when it's at top dead center. This will show that the crank and flywheel are matched up together and the timing is probably where it's supposed to be. If this is the case you may have a bad coil.
I've seen an aftermarket crank for an MS 250 that the keyway was in the wrong place, and it would give a fine spark but of course it wouldn't fire because the timing was way off.

 

[L34]

Good spark outside cylinder doesn't mean it will fire under compression.
Had this with an 064 a few week ago.
Replaced plug and all good.

 

[Oletrapper]

Hmmm out of time perhaps? You would have noticed the stator/crank woodruff key gone though.

Well the saga continues, changed the crank seals and still no life, they came out easy with the lisle seal puller tool, but it definitely seems more difficult to turn over now, I don't believe I seated them to deeply, guess the next step is to buy a vacuum tester.

A couple of things to try.
Remove the muffler and soak in carburetor cleaner for maybe a day. They do get clogged internally. You can't see it. Too much back pressure can cause a no start. You can also try to start with the muffler off.
I use NAPA carb cleaner. A 1 gallon can is about $30.00 and lasts for years.
A sonic cleaner won't remove the carbon build up as the solution won't dissolve carbon but the carb cleaner will.
Remove the carb and the impulse tube from the cylinder. Run a wire through the tube on the cylinder wall that the impulse tube plugs on to. They also get clogged. Probably not your problem as you said the crankcase was full of fuel but clean it anyway.
I'm not sure about the flywheel key on the 026, but the 029 the key is molded into the flywheel and not replaceable. If it shears, even partially, that's a new flywheel. Spark timing is critical.
Good luck and keep us posted. OT

 

[Mad Professor]

Possible... But I only have the low jet 1 turn out from bottom, you would think it would still fire up on that

Problems with metering needle/seat can cause flooding too.

 

[Old2stroke]

As mentioned above, you have to be sure it isn't just badly flooded. When an engine won't start, the first thing you have to do is pull the plug and see if it is dry or soaking wet.