If the engine starts and runs, there isn't a problem.
If the plastic filter is installed correctly, the fuel comes in to the housing and runs down to the lowest point. It passes through the paper and when the fuel reaches the level of the outlet, it flows into the carb.
When the float valve closes the fuel stops flowing. If the filter is horizontal it will rarely be more than 1/2 full, if the outlet is lower than the inlet there will be even less. There is no air bleed to remove the air from the can.
The only way it will be full is if you have it in the vertical line with the outlet on top, then it has to push all the air out as it fills to the outlet.
If you had it in a vertical line flowing down, you would be lucky to see 1/4 inch of fuel.
