I've never been stumped by a saw until now.... Stihl 026

[StihlGuitar]

Well I haven't been stumped by a saw in years but this little rat bastard is driving me back to insanity. Its a '94 026 in great shape, had it running for 2 shakes of a lambs tail and couldnt lean it out enough to keep it running (weird, I know.) So I tore it down, replaced impulse line (it was not leaking but had become rather pliable on the carb end, checked fuel line, checked intake boot, vac tested it (no leaks) cleaned the carb (wt194 which are my fav) put it together and couldn't get it to start. I tore it down again, removed cylinder and piston for inspection....perfect, I don't think the cylinder had ever been off the saw and both p/c were in nice shape. I put the p/c back on, vac tested again in several positions, popped the flywheel to see if the key had sheared and everything was intact. The coil has a nice blue spark. I put it back together, it fired for a second then it wouldn't start. It won't start with fuel added to cylinder either. The only thing I can come up with is perhaps its getting too much fuel from the carb??? If I recall correctly aren't these saws more temperamental in regards to flooding? I dunno, I just have never run out of ideas until now....any input would be appreciated.

 

[diggers_dad]

I had a similar problem that was resolved by a new spark plug. I later learned that sometimes a weak plug won't fire under the extreme pressure of the combustion chamber. Beyond that, I'm as stumped as you are:msp_confused:

 

[Somesawguy]

Is the plug wet?

 

[StihlGuitar]

i tried 2 plugs

I tried 2 plugs although both were used. one bosch and one champion.

 

[StihlGuitar]

yup

Is the plug wet?

yes

 

[Simonizer]

Start it up with hemostats on the fuel line. If it runs great for a few secs release the stats and see if it loads up. That will point directly to over-fueling.

 

[StihlGuitar]

Start it up with hemostats on the fuel line. If it runs great for a few secs release the stats and see if it loads up. That will point directly to over-fueling.

good idea.

 

[StihlGuitar]

Start it up with hemostats on the fuel line. If it runs great for a few secs release the stats and see if it loads up. That will point directly to over-fueling.

in the absence of hemos I zip-tied a tweezers around the fuel line. i had the saw sitting upside down with the plug out already to purge any excess fuel. I put the tweezers on, put the plug in and it fired right up. Thanks. So i guess a carb rebuild is in order??

 

[brages]

Check the choke is working right? doubt that's it, though.

 

[StihlGuitar]

Start it up with hemostats on the fuel line. If it runs great for a few secs release the stats and see if it loads up. That will point directly to over-fueling.

Check the choke is working right? doubt that's it, though.

no, its the opposite of that...lol. it fired with no filter on and with a pinched fuel line.

 

[RED-85-Z51]

If the Inlet needle and diaphragm are good, Ive had a couple Stihls come in that overfueled no matter what and they ended up having bad...well Im not sure what you call it, its like a captured disc that allows the fuel into the venturi...they were bad from Ethanol and overfueled no matter what.

Also had an Echo CS-341 do it as well.

 

[StihlGuitar]

I tried a different diaphram out of another wt carb but switched it back when it didn't work.

 

[Adirondackstihl]

I tried a different diaphram out of another wt carb but switched it back when it didn't work.

You pulled the P&C before a simple carb repair kit? Did you pull the needle? Set metering lever height? The saw is 18yrs old.....I woulda started with a carb rebuild....just sayin.

 

[CWME]

Did you check the metering lever height? Try lowering it a bit. Don't want to insult you but have you checked that the gaskets and diaphragms are in the right orientation? Got a 036 that the metering lever was set to high by someone else's attempt at fixing it. I also switched places of the gasket and diaphragm once and flooded the saw in error:help:

 

[cajunhillbilly]

Not just Stihl saws, I have a junkie little 14" Homelite 33cc only a year or two old, only used a couple of times. A guy gave it to me. He had it in the shop and they couldn't figure out why it was flooding, or didn't want to. The case\cyl would fill with gas. If you let it sit overnight it won't start the next day till you turned up upside down and drained it. I must have taken this carb off 10 times and reset the metering lever. I have it running but still not totally right. I think its a malfunction with the carb itself. This saw is not worth buying a new carb, but I hope another one comes along to try just to put this to rest. Good luck with yours.

 

[StihlGuitar]

You pulled the P&C before a simple carb repair kit? Did you pull the needle? Set metering lever height? The saw is 18yrs old.....I woulda started with a carb rebuild....just sayin.

really? I'd rather not order a rebuild kit until I take the 5 minutes to pull the cylinder and see if the carb is worth fusing with. I don't keep carb rebuild kits around seeing as I have to use one every 50th saw or so....I've had a lot more scored pistons than failed carbs...

 

[watsonr]

really? I'd rather not order a rebuild kit until I take the 5 minutes to pull the cylinder and see if the carb is worth fusing with. I don't keep carb rebuild kits around seeing as I have to use one every 50th saw or so....I've had a lot more scored pistons than failed carbs...

I'm interested to see what you find wrong with the carb by pulling the cylinder?

 

[Adirondackstihl]

really? I'd rather not order a rebuild kit until I take the 5 minutes to pull the cylinder and see if the carb is worth fusing with. I don't keep carb rebuild kits around seeing as I have to use one every 50th saw or so....I've had a lot more scored pistons than failed carbs...

You couldnt check the P&C through the intake and exhaust ports?

 

[apse]

Did you check for plugged vent and /or plugged exhaust?

 

[powerking]

opcorn: