I've only had CHT/EGT instrumentation for about 6 months. I still lean by ear, then cross-check and fine-tune with EGT. On the ground I lean to the point that adding throttle causes the engine to stumble. With the low throttle settings used to taxi, I usually see somewhere around 1000 degF EGT, but I don't use it to set the mixture. I set the mixture just rich enough for smooth running.Mark Harwood wrote:Miles, Are you doing your aggressive leaning with the help of gauges or are you using the the by ear method? When I questioned my engine builder on this topic, he said to use only 100 LL and lean it on the ground and in the air as you are. Can you detail your " aggressive" leaning techniques. Do you have the original mixture control? Thanks, Mark
I had a vernier mixture control installed 3 or 4 years ago after my original cable broke. The vernier control makes it a bit easier to make small changes, especially in rough air.
For the initial cut at leaning for cruise, I push the button to disengage the vernier feature and pull the mixture until I detect a little roughness, then use the vernier feature to richen to just smooth, or a little more for max RPM, depending on whether I'm going for best economy or best power, respectively. For slightly better economy, I can reference the EGT to lean until the first cylinder (almost always #5 on my engine) peaks, usually around 1450 degF, then richen to around 1425 or so.
The vernier mixture and CHT/EGT instrumentation on this low-thyroid carbureted engine are probably suit clothes on a hog, but I like them anyway.
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Miles