I have an Easysport with an OS 46 engine. It has a remote valve on it and it ran very well. Yesterday, I took flew it and had a good flight. When it landed the oil from the exhaust was a little darker than it had been, so I turned the needle valve a couple clicks richer. Then I fueled up and took off again. It didn't seem like it was running quite right. I throttled down and started to make my approach when the engine died. I dead-sticked into a bean field with no damage. A friend of mine came over and we started the engine back up again. We tuned it to where we thought it sounded right, held it up and revved it up and down several times. It sounded like the plane of old. I refueled it again and took off. It flew well and when I looped it, it had plenty of power and ran like the plane of old. I did a loop and started around again and then engine died again. This time I had altitude and time and did a proper landing on the strip. I took it back to the pits and looked at the fuel line. There are two feed lines to the engine. One
from the tank to the remote needle valve and one from the remote needle valve to the carb. The line from the needle valve
to the carb was empty and the one from the tank to the needle valve had a large air bubble in it. I am going to take the tank out to test it for air bubbles, but how do I test the needle valve for blockage or air leaks? I thought I might take the needle off of the valve and blow it backwards from the carb side while pinching off the fuel lines. I also think I am going to replace the lines as a precaution. Do I replace the remote valve as a precaution as well? Any thoughts.

Thanks

Edited By the way, I checked the clunk after the less than stellar landing in the beans and it was at the back of the tank where it should be. Sorry for not including this in the question.

tke the remote needle valve off and put it in a bowl of water (keep fuel lines attached and blow through them), if there is a leak in the RNV it should bubble in the water, strip down the NVA (make note of the settings) and check all the seals and o-rings, you may want to try replacing the fuel tubes aswell, even a tiny pin ***** can cause problems

Did you shake loose the clunk so it was no longer "stuck" at the front of the tank from the deadstick landing?

This probably too late but if start the engine and run it at full throttle take note of where the bubbles are....if there are no bubbles from the tank to the RNV then there is no leak external of the tank..if there are bubbles from the RNV to the carb then the RNV or its line is leaking...if when the tank is full there are no bubbles but bubbles appear after you have ran a bit then there is a leak internal of the tank...
Let us know what you find