Gascolator question

[Sturgill]

I am troubleshooting a fuel issue on a 1960 C180 with a O470R. Stock. It has a glass-wall gascolator. I notice that it does not fill up 100%. It stays about 80-85% full. Should I consider this normal, or does it indicate a supply problem upstream?

 

[skywagon8a]

Just thinking out loud.

Air does not flow downhill in a fuel feed line.....so a supply problem generating air upstream is unlikely.
Air bubble in the glass....why? An outlet restriction or the outlet is below the air bubble.
A method to test. Disconnect the fuel line at the carb....run the fuel into a container at full gravity flow to observe the air bubble action. Is there full flow? Does the bubble remain?
The primer sucks fuel from the top of the gascolator. Does running the primer remove the air bubble?

What is the noticed fuel issue? Have you pulled the carb bowl drain plug, allowing a strong flow to flush out any possible dirt or water in the bottom of the bowl? This sometimes solves small carb issues.

 

[Steve Pierce]

have you taken the fuel line loose at the carburetor. Air gets trapped sometimes. I see it after I have worked on the system, I have to sump the air out.

 

[Sturgill]

We just did a flow test at the carburetor. There is a serious restriction upstream, probably at the finger strainers.

The gascolator filled up to 100% as soon as fuel started flowing. Mystery solved.

Now we will drain the tanks and pull the finger strainers for cleaning, and flush the tanks before reinstalling.

thanks for the responses.

 

[skywagon8a]

Before you pull the finger screens at the tanks, what did you do for a flow test? Pulling the tank finger screens can destroy the fuel tank bladders if they are old. The finger screens are large and long. You would have some serious tank contamination to clog them. You can drain the tanks, then using mirrors and lights look at the screens through the filler opening.

There could be a restriction in the hose between the gascolator and the carb.

 

[cubpilot2]

Be sure to check the vents for blockage. Will act very similar to a flow restriction. The tank strainers are very course and will only stop the large stuff.