Stihl 020av carb issues

[cmuwriter1982]

I am trying to get an old Stihl 020av running. Can't find a replacement carb or even an apples to apples carb kit. Tried a lot of kits but can't get the saw to run without bogging. Any suggestions on what to do next? It's a very cool little arborist saw. Runs and idles well just can't get that high circuit going.

 

[Vintage Engine Repairs]

Yeah the issue is with AM carb kits, the little kidney shaped diaphragm that sits over a drilling directly into the throat of the carb needs to flex and seal. The diaphragm on AM kits is too thick compared to the normal oem and this stops the drilling being sealed and thus you’re getting unmetered fuel as it’s not passing the screw.

Cut some of the excess diaphragm where the valve connects to the main part of the gasket and you’ve essentially made it easier to flex and the vacuum can thus overcome the resistance of the material. This will solve your issue.

 

[cmuwriter1982]

Yeah the issue is with AM carb kits, the little kidney shaped diaphragm that sits over a drilling directly into the throat of the carb needs to flex and seal. The diaphragm on AM kits is too thick compared to the normal oem and this stops the drilling being sealed and thus you’re getting unmetered fuel as it’s not passing the screw.

Cut some of the excess diaphragm where the valve connects to the main part of the gasket and you’ve essentially made it easier to flex and the vacuum can thus overcome the resistance of the material. This will solve your issue.

A lot of the kits and parts manual for the saw show that there is just a kidney shaped gasket on that side. Would it be better to try to secure an OEM gasket set in your opinion? If so what should I get. Also is this car a WA1? I can't seem to find anything for WA1A. Thanks for the advice. I'm a novice.

 

[Vintage Engine Repairs]

A lot of the kits and parts manual for the saw show that there is just a kidney shaped gasket on that side. Would it be better to try to secure an OEM gasket set in your opinion? If so what should I get. Also is this car a WA1? I can't seem to find anything for WA1A. Thanks for the advice. I'm a novice.

There should be a diaphragm and gasket under the metal plate.

 

[bulletpruf]

Very interesting! I have 3 of the 020AV saws and one is giving me problems now. I'll have to try this fix. Thanks!

 

[stihltech]

Pressure test the fuel fitting with the carburetor installed. Found many leaks where the intake manifold mates to the carburetor. A very fussy saw to get right, but pretty unbeatable for its size class. A pressure and vacuum test is a must. Lots of cylinder gaskets and pulse hoses.

 

[topher88]

This is what was on my 020AV. Is this not the correct carb?

 

[DND 9000]

It is the right carburetor. Carburetors used on a model change from time to time.

 

[stihltech]

Again, look beyond the carburetor. Until the rest of the saw is up to snuff you will always have an issue. Maybe I missed it, is it electronic?

 

[president]

Again, look beyond the carburetor. Until the rest of the saw is up to snuff you will always have an issue. Maybe I missed it, is it electronic?

I thought the correct carb is a wt15?

 

[stihltech]

I thought the correct carb is a wt15?

Again, look beyond the carburetor. Too many of these were cured by repairing an air leak between the carb and intake boot.

 

[DND 9000]

I thought the correct carb is a wt15?

This one was also used on that model, but which carburetor is on the saw depends on the age and year of manufacture. If I know it right the WT-15 carburetor came 1984.

 

[stihltech]

OK what I need to see is the mounting flange for the carburetor to intake boot. That is what makes the difference.

 

[president]

OK what I need to see is the mounting flange for the carburetor to intake boot. That is what makes the difference.

T1!