Sound's safe & normal but at 5200 you are wasting fuel at 13.3
a/f. Lean it out if your system allows it.
Tracy
----- Original Message -----
Sent: Saturday, June 04, 2005 5:36
PM
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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