I too have never had a problem with a Perry pump. I have even used it sucessfully when the tank is high enough to cause fuel siphoning. I simply clamp the fuel intake line with a hemistat before filling, then when filled open the carb, open the hemistate for a second to prime the carb, then start, then quicly remove the hemistat. This is not possible with many cowled engines.

I use the hemistat for installations where the fuel tank does not siphon as well. In that case I do not add the hemistat till I prop the engine a few times to pump fuel into the carb. That is how I found that it works with tank levels that are too high. I did not even know the plane siphoned fuel till I didn't start it for a while after filling the tank, then noticed raw fuel unde the plane. I had flown it several times before noticing this. It did not siphon the fuel quickly and did not have time to flood the carb if started right away.