Shane,

Thanks for the clarification.  I should not have said “leave Low Boost on all the time.”  I don’t use Low Boost until after run up, to verify the engine driven pump is working.  We flew for over 200 hours without Low Boost with no noticeable problem.

Steve Colwell

I agree with Steve except I leave the low boost off during taxi and run up but turn it on before the takeoff roll and leave it on until back on the ground.  My mechanic was told by CJ Aviation (828 871 0421) who overhauled my fuel  pump,  the pump has ran continuously in tests for over a 1,000 hours w/o failure.   I also recommend you purge each tank before start up to remove any air in the lines which should prevent a loss of fuel to the engine when switching tanks.

Shane 

IV-P 420 hrs  

From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Steve Colwell
Sent: Wednesday, September 24, 2014 6:13 AM
To: Lancair Mailing List
Subject: [LML] Mechanical Fuel Pump Oddities

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