Stihl 026 Gas Leaking Problem

[donwheeler]

I have a Stihl 026 saw that I bought new several years ago but have not used much in recent years due to a gas leakage issue.

The following are a couple of symptoms:
The saw starts just fine but will only run 3/4/5 minutes and then just quits, as though it was choking itself.
When I set the saw on a storage shelf and return to it a day later, it is sitting in a puddle of gas.

I've checked the fuel hose, it appears to be fine. No cracks or breakage.

I've proved to myself that the tank itself does not leak. I did learn that if I pull the fuel hose off of the carb inlet elbow, gas will siphon up the hose and spill on the saw above the fuel tank. I am also quite certain my leakage problem is above the fuel tank in the area of the carburetor.

The saw has a Walbro carburetor with the following numbers on it:
WT493A, and 600.

I don't know much about fixing chainsaws, but some thing I've noticed seems peculiar to me.

The carb inlet elbow has red goop on it as though it might be some sort of sealing agent. I am able to not only move the inlet, but can turn it around and around. I'm wondering if this could be the cause of my leakage issue. Please refer to the attached picture.

I have another question, related to the tank vent. Mine is a roundish plastic cap with tiny filter in it, and a stem looking rubber valve. If I have the proper names, there is a self-tapping screw visible on the outside of the plastic cap, and a very tiny grub screw visible on the inside of the cap. My question is, I do I know how to adjust these screws. I dubbed with the self-tapping screw and forgot how it was set.

If the problem is not related to the inlet elbow, perhaps some one could suggest other things for me to inspect and test.

Any and all help or comment will be greatly appreciated.

Thanks,

Don in Maine

 

[ttyR2]

My 026 Pro has what I think is a newer style fuel tank vent/filter without the taller plastic piece with the screws. There's a white plastic cap that presses on over the hard plastic filter element, and underneath that is the umbrella valve that allows air into the tank, but not back out. I've had pressure build up in the fuel tank, but never had that cause any problems with the carb.