This is my first plane with one of these fueling valves on it. I have watched for air bubbles in the fuel line but haven't seen any up to this point so I have tried to make sure the engine is tuned properly before going through the trouble of dismantling the tank and lines that are difficult to access on this plane. I am at the point where I think replacing the fuel tubing may be in order which would then also make it wise to pull the tank. I have been avoiding the whole thing since pulling the tank will probably require taking out the servos to get access.

Before I do anything else I am going to try another tank with known good fuel tubing on the outside of the plane to make sure it isn't strictly a problem with the engine. I would hate to dismantle the plane only to find out that isn't the problem. I may also try bypassing the fueling valve before pulling the tank. Better to take things one step at a time.

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EDIT:
I have since tried another fuel tank and the engine still exhibits the same characteristics. Looks like the DuBro remote fueling valve is working just fine at this point. The search continues...