Originally Posted by Tired Old Man

Needles 101: clockwise is leaner, counter clockwise is richer. The low needle is the one closest to the engine and might have an "L" cast into the carb. The high needle is the one farthest from the engine and might have an "H" cast into the carb next to it. Gas needles get turned very small amounts. Small adjsutments can make big changes. It's not a glow engine so don't do 1/2 turn adjustments. It will usually have been much too much. 1/16 of a turn can be the difference between "just right" and "sucks".

Secure the plane, leave the cowl off, start the engine. Let it warm up for a minute or so at half throttle before touching anything.

Run it up to wot. Lean the high needle, the one farthest from the engine, until the engine reaches and just passes the highest rpm point. Just enough so the high rpm falls off a little. Pay attention to where the slot in the needle was positioned. Now back off the same needle until the rpm picks up and backs off a little again. Put the needle roughly halfway between thse two spots. If you're good, or a little daring, lean it back out to peak rpm and leave it there. No need to run rich. Peak is perfect once you get the low right most of the time. Those times are noted later.

Let the engine continue at idle for a few minutes to cool down. Then advance the throttle to about 3,500-4,000 rpm. That's usually just a little less than 1/2 throttle. Turn the low needle (lean or rich depends on where it had been before starting) until the engine picks up a lot of rpm. Make that, picks up to where the engine reaches a peak and falls off a little. Back that needle up (richen) until the engine hits peak rpm for the middle throttle position. Reduce the throttle to idle and wait about 30 seconds.

Now advance the throttle rapidly. Te engine will probably go "wuff" and not throttle up well. Richen the needle about 1/8 turn with the engine at idle. Wait about 30 seconds. Advance the throttle rapidly again to wot. What did the engine do? Did it go "wuff" like it ran out of gas? If so, that's what it did because the low needle is still lean. Richen up another 1/8 turn and try again.

OTH, did the engine sputter like it was wet? If so it's rich and you need to lean the low needle about 1/2 of the turn amount you used when you richened it. Keep following this process until the throttle response is as crisp as you can make it. Then go fly.

In flight you get to note how good your tuning was. There is generally a little bit of low end needle work still left to do after it gets in the air. Listen to your engine. Does if "wuff" when you throttle up or sputter and burbal? Each sound tells you what you need to do, in very small increments, when you get it back on the ground. Feel fortunate. Your needles are at the back of the engine and easy to access with the engine running. Have sympathy for those with needles up front. They get to stop their engines every time they have to twist a needle, and start it back up to see how well they did.

After the high needle is peaked, 99% of the time any further adjustments will be done at the low end. Too lean on the low end could require the high end be richened. Some engines are finicky that way. This is that "later" part. The DLE 111 and the BME 116 both fit that shoe.

For the guy that complained about not giving any tuning instructions. Why didn't you step up to the plate?

This was the brief version. The long one involves a bunch of instrumentation. Enjoy.

Originally Posted by Reza

Hi Bart,

It's so good to hear from you! You had the 85" or was it 86"! I remember you had a deadstick in the first few flights and you had to rebuild the front of the plane! Do I remember correctly or am I wrong?