Stihl 026 pro carb fuel/air issues

[Tom-Gobowen]

Hi, Last week I picked up a new to me stihl 026 pro last week and I can't get it running with the air filter on. It will run without it on with no problems but as soon as I fit the airfilter the revs go crazy and then dies off and stalls. It will then fire up, but won't run with the airfilter on.

 

I've tried cleaning the air filter, cleaning the carb (altho thats from another 026 so I know works fine). I've tried setting the saw to the factory carb settings. 

 

I guess its now going tobe a process of elimination, but any tips on where to start?

 

Thanks Tom

 

[Stubby]

7 minutes ago, Tom-Gobowen said:

Hi, Last week I picked up a new to me stihl 026 pro last week and I can't get it running with the air filter on. It will run without it on with no problems but as soon as I fit the airfilter the revs go crazy and then dies off and stalls. It will then fire up, but won't run with the airfilter on.

 

I've tried cleaning the air filter, cleaning the carb (altho thats from another 026 so I know works fine). I've tried setting the saw to the factory carb settings. 

 

I guess its now going tobe a process of elimination, but any tips on where to start?

 

Thanks Tom

 

You say you have cleaned the filter but perhaps it is still blocked ?  Try a new filter , can't hurt to have a spare if its not that .

[adw]

Does it run really rich and cut out with the filter on, or lean off with the filter on? Does it restart easily once the filter is removed after stopping?

[Tom-Gobowen]

26 minutes ago, adw said:

Does it run really rich and cut out with the filter on, or lean off with the filter on? Does it restart easily once the filter is removed after stopping?

I think it must lean off as soon as you tighten the airfilter (feels/sounds like last few seconds before you run out of fuel) will check how it restarts tomorrow .

Edited January 16, 2022 by Tom-Gobowen

[adw]

No fan of Stihl machines, however the ones I have seen have compensator carbs, so the metering side of the carb will not have a a hole to atmosphere in it, this is because there will be a channel via the air filter to the flip side of the diaphragm, so is this blocked or covered over?

[Con]

You're not restricting a fuel line when putting the air filter covers back on?

[spudulike]

My thinking is the air filter choke mechanism (it is built in to the air filter) is somehow holding the throttle open when you refit the air filter. 

You will just have to look at this area and you could fit the air filter slowly and see at what point the revs start racing and what part of the air filter housing is fouling the throttle mechanism. 

 

[Tom-Gobowen]

39 minutes ago, Con said:

You're not restricting a fuel line when putting the air filter covers back on?

Thats something I haven't checked, will look at that tomorrow. I did think about maybe  changing the fuel and impulse hose as I plan on keeping the saw a while. Is there much between stihl oem lines and other brands apart from price? Thanks

[ChrisNewport]

Is it the correct air fiter for the saw? There is 2 that look similar but arn't. 

[spudulike]

When you fit the air filter, do you take the choke OFF and then just slide it on to the two threaded rods? The choke mechanism pushes on to the choke plastic lever and NOT behind it!