While looking for clues as to why my L-4 was idling so badly, I happened upon an interesting passage in the J-3 pilot's handbook from 1940. It suggested that the finger screen in the 12 gallon tank be inspected and cleaned of dirt and sediment every 100 hours. I don't know if this had been done in the almost 20 years that I've owned the aircraft. I figured it was about time, especially as I'd resolved to inspect the fuel system from one end to the other anyway.
Removing the screen for inspection is not a difficult job, but the tank has to be drained and the fuel shut-off valve removed. I found that the screen was perfectly clean. This was also a chance to visually inspect the inside of the original tank, which is bright and clean as well.
I'm thinking that as long as your fuel samples and gascolator and carb screens are clean, then the 100 hour (or annual) finger screen inspection is probably not necessary.
Removing the screen for inspection is not a difficult job, but the tank has to be drained and the fuel shut-off valve removed. I found that the screen was perfectly clean. This was also a chance to visually inspect the inside of the original tank, which is bright and clean as well.
I'm thinking that as long as your fuel samples and gascolator and carb screens are clean, then the 100 hour (or annual) finger screen inspection is probably not necessary.
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