Hi Yvon, what type of fuel system are you using? -- Ian


-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]On
Behalf Of Géraldine Berger & Yvon Cournoyer
Sent: Saturday, June 04, 2005 5:37 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] BAR GRAPH AIR/FUEL GAUGE


  I fly a Zenair Zenith 200 with a l986 13B.  I have installed a
Cyberdyne Instruments bar graph air/fuel gauge (P/N 7009). The O2 sensor
is located ~31 inches from the exhaust ports. The O2 sensor is not a
Cyberdyne Instruments part. It is an aftermarket universal single wire
sensor. The readings of the air/fuel gauge are baffling me. At idle of
1100  rpm and MP of 14.1-14.2 inches/mercury, the air/fuel gauge shows a
rich condition of ~12.7:1. That is where the engine runs best at idle.
At full power static of 5200-5250 rpm and MP of ambient (~30
inches/mercury), the air/fuel gauge reads rich ~13.2:1. However, when I
retard the throttle to 3000-3500  rpm, at a MP of 17.0-17.1
inches/mercury, then the air/fuel gauge reads lean at ~16.0:1. The
engine runs quite evenly at all power settings but I wonder if the
variations in fuel mixture are normal and safe?
Yvon.

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