I don't know what is going on with RCU, but I still have not been getting notified to replies to the forums.

Anyway, I currently am fighting with an O.S. .40 SF that is hard to prime, and the fuel rapidly flows back to the tank. Very frustrating! It runs great in the air for a few minutes, then dead stick! I have installed a check valve in the line to the carb, which makes priming easier, but it still doesn't run right. All I can think, is that for some reason, there is an excesive backflow of air through the carb to the tank. Apparently, this isn't an uncommon problem. I have a K&B 1.00 doing this right now also. I experimented with the K&B by adding the uniflow tank set up, and it didn't work well. If anyone has an answer to this one, many people with many types of engines will be greatful. I ordered a Perry carb yesterday for the K&B. If that solves the backflow problem on it, I would be inclined to believe the problem is in the carb on all these engines. I will keep you posted!

Andy