Kevin,

I had the same problem on a warm day with warm fuel from an above ground tank.  My solution is to leave Low Boost on all the time.  The Dukes pump is not rated for continuous operation but mine is still running at 200+ hours.  Another plus is, if your engine pump fails on takeoff, Low Boost will probably keep the engine running (maybe at reduced power but still running).  I believe Continental recommends Low Boost above 10,000’ so the best explanation could be “they do that”.

Steve Colwell  IO-550 Legacy