No more flooded carb due to tank pressure buildup

[link]

It might not be a problem on all saws but it certainly is on some.
My saw have a one way valve in the gas tank and it lets air in so it doesn't create a vacuum in the tank when the engine is running, but it doesn't let air (or gas) out so when the gas evaporates in the tank it creates a pressure. This pressure pushes fuel up to the carburetor and it totally floods, and so when ever the saw has sat a while it will be a nightmare to start it.

So I have a bag of these one way tank valves and I have opened one up, and I have made a tiny puncture hole in the rubber membrane. This puncture hole is very small like a needle point, and it lets air leak slowly out through it without any pressure needed for it to do so.


Then I have modified my tank vent, ripped out the internals from it and installed a brass tube through it.


Making a small bend in the tube was necessary to make it fit back in place. I have used a piece of tygon tube between the tank and the valve to make a buffer, if I have the saw upside down and the engine is not running; fuel might get out but only in a very small amount like a few droplets, and the lenght of tube should prevent it by making a delay.

 

[J D]

You are making one part of the saw dysfunctional to compensate for another part of the saw not functioning... if the carb is flooding due to the pressure in the tank then the metering valve isn't sealing properly. The carb inlet should hold 12+ psi indefinitely without leaking. If you're getting more than that in your tank it must be helishly hot where you're keeping them

 

[link]

You are making one part of the saw dysfunctional to compensate for another part of the saw not functioning... if the carb is flooding due to the pressure in the tank then the metering valve isn't sealing properly. The carb inlet should hold 12+ psi indefinitely without leaking. If you're getting more than that in your tank it must be helishly hot where you're keeping them

I hear you say "dysfunctional", but I don't see it happening.

 

[stihltech]

A better approach would be the old style hose a grub screw vent. Yould don't want to remove ALL the pressure in the tank. But you are not correcting the problem. Ditto on the inlet needle issue being the cure. Correct inlet lever height is critical on these carburetors.