Stihl 011AV won’t run

[Antney02]

I have read many of the posts on this saw and am unable to find one with my exact problem.
I was given a 011AV white case. The fuel and vent lines were shot.
I have replaced: lines, filter, plug, fuel, carb. Cleaned the entire saw, including exhaust and screen. Piston looks pristine with visual inspection.
Symptoms won’t run unless I put gas directly in the carb. Then runs and dies. So I have spark.
I checked the Reed valve and gaskets and all look ok. I have the screw in the vent line. I pulled gas from the tank via the fuel line with a small syringe. I even replaced the whole carb (after cleaning and rebuilding the old one extensively).
Using ethanol free fuel premix.
At a loss for solution at this point, I don’t even know what else to try.
Thanks for any feedback in advance.

 

[djg james]

I have read many of the posts on this saw and am unable to find one with my exact problem.
I was given a 011AV white case. The fuel and vent lines were shot.
I have replaced: lines, filter, plug, fuel, carb. Cleaned the entire saw, including exhaust and screen. Piston looks pristine with visual inspection.
Symptoms won’t run unless I put gas directly in the carb. Then runs and dies. So I have spark.
I checked the Reed valve and gaskets and all look ok. I have the screw in the vent line. I pulled gas from the tank via the fuel line with a small syringe. I even replaced the whole carb (after cleaning and rebuilding the old one extensively).
Using ethanol free fuel premix.
At a loss for solution at this point, I don’t even know what else to try.
Thanks for any feedback in advance.

Same problem with mine. Where did you get the carb?

 

[Antney02]

So I took a shot and got a Zama carb instead of the walbro. They appear identical, not sure if they really are, but the symptoms are the same regardless.
eBay https://www.ebay.com/itm/2338110810...Ko-e2stSUe&var=&widget_ver=artemis&media=COPY
It’s definitely the correct carb for 011AV, but IDK if it matters that it’s not original walbro?

 

[ZeroJunk]

Make sure the impulse path is clear and that the hole in the gasket and in the carb line up with it.

 

[Antney02]

Pardon my ignorance, if by path you mean I can look down thru the carb and clearly see the Reed valve, then yes it’s clear. If you mean something else, you’ll have to explain it to me.

 

[Antney02]

I have read many of the posts on this saw and am unable to find one with my exact problem.
I was given a 011AV white case. The fuel and vent lines were shot.
I have replaced: lines, filter, plug, fuel, carb. Cleaned the entire saw, including exhaust and screen. Piston looks pristine with visual inspection.
Symptoms won’t run unless I put gas directly in the carb. Then runs and dies. So I have spark.
I checked the Reed valve and gaskets and all look ok. I have the screw in the vent line. I pulled gas from the tank via the fuel line with a small syringe. I even replaced the whole carb (after cleaning and rebuilding the old one extensively).
Using ethanol free fuel premix.
At a loss for solution at this point, I don’t even know what else to try.
Thanks for any feedback in advance.

Update, I decided to recheck the vent line to make sure I hadn’t crimped it when I reinstalled it, or put the zip tie on too tight, but no issues there. It does seem that there is no fuel drawing up through the line from the tank. The filter is new and is fully immersed in fuel.

 

[SteveSr]

Update, I decided to recheck the vent line to make sure I hadn’t crimped it when I reinstalled it, or put the zip tie on too tight, but no issues there. It does seem that there is no fuel drawing up through the line from the tank. The filter is new and is fully immersed in fuel.

Why did you replace the original Walbro with a Zama? Stihl may have changed other parts when changing carb OEMs so your Zama may not fit/work. Post some photos of t he saw side of the Walbro as well as the model number etched (usually) near the fuel inlet.

 

[ZeroJunk]

Pardon my ignorance, if by path you mean I can look down thru the carb and clearly see the Reed valve, then yes it’s clear. If you mean something else, you’ll have to explain it to me.

In the phenolic piece that the reed valves are riveted to there is a hole that goes in to the crankcase. That hole lines up with a hole in the carb gasket , and a hole in the saw side of the carb. That hole is what provided the impulse from the changing pressure in the crankcase to make the carb pump.

 

[Antney02]

In the phenolic piece that the reed valves are riveted to there is a hole that goes in to the crankcase. That hole lines up with a hole in the carb gasket , and a hole in the saw side of the carb. That hole is what provided the impulse from the changing pressure in the crankcase to make the carb pump.

Thank you, I’ll check that.

 

[Antney02]

Why did you replace the original Walbro with a Zama? Stihl may have changed other parts when changing carb OEMs so your Zama may not fit/work. Post some photos of t he saw side of the Walbro as well as the model number etched (usually) near the fuel inlet.

I picked the zama as the walbro isn’t available and I wanted to rule out the carb as the source of the problem. I looked at the images and they were similar enough that I believed they were compatible. I still have the rebuilt walbro and with either carb installed it has the same symptoms. So my assessment is that it’s not the carb that’s the issue. Moving forward I’ll do all the testing with the original carb installed. Obviously this may be flawed logic.

 

[Homer6679]

Update, I decided to recheck the vent line to make sure I hadn’t crimped it when I reinstalled it, or put the zip tie on too tight, but no issues there. It does seem that there is no fuel drawing up through the line from the tank. The filter is new and is fully immersed in fuel.

Sounds like there is an issue with the “pumping” system.

The pumping system works off of positive and negative crankcase pressure. The difference in pressure is transferred through the “impulse line” to the carburetor pump diaphragm. On those old reed saws the impulse line is a hole in the block that the carb bolts to. That hole will line up with a hole on the carburetor. Typically it’s a small hole just outside the main channel or Venturi if you will. Make sure it all lines up and you should have a working fuel system.

I had an 009 (similar saw) that I couldn’t get running for the life of me and it turns out I put the gasket on wrong between the carb and the carb block. And it was blocking the impulse line.

I would stick with the original carb as well. And make sure the the path for the fuel to the carb is all good. The fuel filter and fuel lines should be in good working order

 

[Antney02]

Sounds like there is an issue with the “pumping” system.

The pumping system works off of positive and negative crankcase pressure. The difference in pressure is transferred through the “impulse line” to the carburetor pump diaphragm. On those old reed saws the impulse line is a hole in the block that the carb bolts to. That hole will line up with a hole on the carburetor. Typically it’s a small hole just outside the main channel or Venturi if you will. Make sure it all lines up and you should have a working fuel system.

I had an 009 (similar saw) that I couldn’t get running for the life of me and it turns out I put the gasket on wrong between the carb and the carb block. And it was blocking the impulse line.

I would stick with the original carb as well. And make sure the the path for the fuel to the carb is all good. The fuel filter and fuel lines should be in good working order

Solved. Gasket was indeed reversed. That was 1/2 the issue. The stock walbro carb still has issues. When I installed the zama it fired right up (after priming) and pumped fuel. Side by side carb comparison for those who asked earlier. Apologies for the last image, I forgot to shoot the side of the Zama carb that actually has the Stihl branding.

 

[Antney02]

Thank you everyone for the input.