REFLECTOR: Fw: IO-550 Fuel Flow Issues

[LAURA WALKER]

Brian, my engine is manual mixture and is full rich already. Not sure of my fuel flow numbers, since it didn't really want to get below 760 rpm and continue running. I also had a GRT data recovery problem, which is now solved. My EAA technical counselor overseeing the first start thought it was a badly timed magneto since the engine ran pretty well on the Plasma side. It checked out to be perfectly timed and it was on the first start on the second day when I discovered that it ran quite well on the Low Boost setting. The engine has only run on two separate days so far, so a third time is in order to address these issues. I just got back from my transition course at Velocity, and hope to have the plane in the air around mid November. 


Al, thanks for the advice. That's kind of way I was leaning (i know, very punny) also. I suppose it's just possible that PE tested and set up the engine with no external fuel pump and the mere addition of my boost pump in the line created enough of a restriction to throw things out of whack a little bit. Everyone at Velocity said that EVERY Continental IO-550 engine should have the fuel pressures checked and set before flying, so I'm now in the process of gathering parts and building a twin gauge test rig. After comparing fuel flows from various other high-output, normally aspirated engines (including the rare and seldom heard of GIO-550-A at 350HP) I think I am spot-on with wanting to see 32-34 GPH with the Metered Nozzle pressure between 23.8 - 26.6 PSI.

Bill Walker