026 refuses to idle

[Adirondackstihl]

The Tilly I pulled from it was at 17

Hmm

 

[Mark71gtx]

From some relentless digging online, it appears to lower pop off, you cut the spring until youbget the desired pop off. Maybe that will be my next move...

 

[Mark71gtx]

Not tonight though... right at midnight... time to get ready for bed

 

[Adirondackstihl]

Or try another spring from a donor carb

 

[drf256]

You got an AM carb on it. Notorious for issues. Many do need loctite blue on the LA screw or it just spins. Check the metering lever height as well.

I keep one good OEM Walbro 194 on hand for testing.

If the vac line passed the vac test, I doubt it's that.

You also need to look at what's been changed. The AM tank-see if the boot area is sealing correctly to the carb. Make sure you installed the outer and inner rings in the boot entry.

All I got right now.

 

[Mutley]

Just a thought, but did the rubber manifold get damaged when the carb went on? I had one that did & the symptoms were very much as you describe.

 

[Mark71gtx]

Everything is in place as it should be. The tank is used OEM. Boot looks to be in good shape. Still nice and pliable. I have pressure and vacuum tested the saw twice. Once with the old tank, and once with the replacement tank. Passed both times.

 

[junkman]

How does the piston look ?

 

[Mark71gtx]

Looks nearly new. Machine marks still evident on piston

 

[junkman]

My 026 was running and not idling also ,i got fed up and bought a new oem walbro wt194 off ebay ,now it runs and idles fine ,the other carb i had was a wt194 also i put on a couple years ago new ,they must plug up from sitting .

 

[Mark71gtx]

The carb that came off of it was a Tillotson. I doubt it was original to that saw. The new carb I used was one a guy brought me to put on some 026's I was fixing for him. They would not fit the 026 tank and he told me to keep it. This is the first time it had seen fuel. I am going to try to trim the spring and see what happens.

 

[fossil]

Here's some interesting reading on pop off pressure. The engines they refer to are used for para gliding rigs.

http://inventions.aerocorsair.com/id38.htm

 

[Mark71gtx]

That is one if the articles I read last night, lol!

 

[RI Chevy]

What carb are you dealing with? WT194? Or WT403A? Maybe a bad tank vent?

 

[Mark71gtx]

China special 260 knockoff. The vent leaks fuel, so I doubt it would be too much of an issue. Maybe I am wrong?

 

[Chainsaw Jim]

Try changing the flywheel and maybe the coil.

 

[Mark71gtx]

I don't have a spare 026 flywheel, but I may have a coil or two lying around...

 

[Chainsaw Jim]

There's only so many possibilities here. One of the tests are failing you or you're missing something you've already checked. I'd change out the crank seals unless you know they're fresh to start with. Then I'd practically turn the intake boot inside out looking for a crack that won't expose itself under testing.

 

[Mark71gtx]

In my experience, which is limited, I have found that small air leaks cause the saws to idle very high - or "not idle". I think I need to be use better wording in my problem description. The saw will not run at low rpm. At all. I can start it only when choked first. Once I click the lever up one notch to "high idle" it will start and run in that position. As soon as I pull the trigger, it will rev as it should, but once the trigger is released, it will knock off unless I pull it again. I normally have to "pump" the trigger to keep it from knocking off. Sometimes it still knocks off. It will only start back when choked again. Now, with this pertinent information that I really should have put in the original post available, what do you guys think?

 

[jb-chainsaws]

I know it sounds simple but always worth checking, can you crank the LA screw up til it holds an idle then fatten up the low side to stop the creep? Or will that not even work?

Sure does sound like a small air leak to me, had an 026 doing the same thing not 2 weeks ago, turned out to be the intake boot had gone stiff where it meets the carb and wasn't just sealing perfectly