026 refuses to idle

[Mark71gtx]

Tree service guy dropped off an 026 that wouldn't run. I fooled with it a bit and got it to start, but the rpm shot to the moon so I shut it down. The tank was broken at the rear handle, so I replaced it with a 260 tank. I put a new AM 260 carb on it whrn I replaced the tank. I pressure and vacuum tested the saw and it passed flawlessly. I did rotate the flywheel during the test. I replaced the fuel line and filter. Line is OEM Stihl. It will still not idle, or even get close to idling. High rpm seems fine. The coil was covered in crud, so I cleaned it and the flywheel off and regapped it with a HL Supply business card (I have a bunch of them now for some reason...) what to check next? Any ideas per the symptoms? Piston looks great with machining marks still present. I removed the air filter and tried it as well. It hits right away when being choked.

 

[fossil]

Long shot; if the throttle linkage isn't bent holding it open, maybe someone fiddled with the carb and put the throttle shutter in backwards.

 

[Mark71gtx]

It doesn't shoot to the moon anymore, it just will not idle. Carb is new, but symptoms are similar. I am leaning toward the impulse line, but it passed both pressure and vacuum tests. Just looking for any other brilliant ideas before ordering more impulse lines. I know none of the local dealers stock them. They are all freaking catalog stores when it comes to parts. That is what irks me about Stihl. Don't sell their parts online, but don't stock $hit...

 

[Jimmy in NC]

It doesn't shoot to the moon anymore, it just will not idle. Carb is new, but symptoms are similar. I am leaning toward the impulse line, but it passed both pressure and vacuum tests. Just looking for any other brilliant ideas before ordering more impulse lines. I know none of the local dealers stock them. They are all freaking catalog stores when it comes to parts. That is what irks me about Stihl. Don't sell their parts online, but don't stock $hit...

Identical problem with two carbs or has the problem changed?

 

[Adirondackstihl]

Plug tightened down?

 

[Mark71gtx]

Problem is "similar" neither would idle. Plug is tight. It would have failed pressure and vacuum otherwise.

 

[Mark71gtx]

The reason I am leaning toward the impulse is because it will fire right away on choke.

 

[Adirondackstihl]

Problem is "similar" neither would idle. Plug is tight. It would have failed pressure and vacuum otherwise.

True
But I didn't know what method of vac/press you used.

You press/vac the carb?
Pop off pressure?

 

[Mark71gtx]

Didn't mean to sound condescending at all. I could have worded that response better. I have never done a carb pop off test, and honestly don't know how...

 

[Mark71gtx]

I always test through the impulse line when there is one. Other saws I use a boot that slides in the plug hole and slide a cone shaped fitting in it. It seems to work well.

 

[Hoggwood]

Will it idle with the air filter off? Had an aftermarket one with a shutter that stuck a bit and waaay too much glue in the flocking. Caused a few problems. Mostly over rich symptoms though. Went with a new OEM filter. Golden.

 

[Mark71gtx]

No change with filter removed other than the challenge of starting it with my thumb over the carb...

 

[Adirondackstihl]

Didn't mean to sound condescending at all. I could have worded that response better. I have never done a carb pop off test, and honestly don't know how...

It's all good mang.
I didn't take it the wrong way.

Pop off is simple

 

[Mark71gtx]

Cool deal. Enlighten me on the pop off...

 

[Adirondackstihl]

Cool deal. Enlighten me on the pop off...

Pop off is the amount of pressure required to "pop" the needle off its seat. Pressure is determined by the metering spring.

I'm not great at explaining stuff, but I think Mitch or Scott has a great video.

BRB boss...

 

[Adirondackstihl]

Can't find the one I'm looking for, bug there is a ton of pop off vids on the Tube

 

[Mark71gtx]

Pop off is about 22

 

[Adirondackstihl]

Pop off is about 22

Seems excessive

I remember Scott saying 15lbs in a video.
Another member saying 12lbs in a phone convo

 

[TJ the Chainsaw Mechanic]

Brand new carb though, should be perfect!

 

[Mark71gtx]

The Tilly I pulled from it was at 17