Grease Monkey

I have a clear fuel filter in the engine compartment ahead of the mechanical fuel pump. There is a small air bubble in the filter (less then the size of a pea) but when I start the engine the fuel in the filter will drop to less then 1/4 of the filter.

After I shut the engine off the filter will slowly fill back up with fuel. I changed the filter and tried to bleed the air out but same problem.

I thought I might have a air leak on the fuel line but if I put a bulb on the hose from the fuel tank I can suck fuel with no problem.

This is also with it cold so not a vapor lock.

Wachuko

These are low pressure fuel systems with the carbs... what you are describing is normal. The fuel filter is never completely full, there is always some air in it.

Just make sure all the rubber lines are in perfect condition. Replace if you are uncertain, cheap insurance.

Again, behavior described is normal...

Grease Monkey

Thanks, fuel line in the engine compartment look new. I need to check the fuel line from there back to the tank. I did this on a 914 a few years ago replaced the plastic fuel lines that run through the tunnel with stainless steel. I am guessing the 912 is similar?