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Starting
Avoid running the engine without the wings installed on the fuselage. Without the mass of the
wings, vibration will be very pronounced.
Check that prop bolts are tight and spinner is secure.
Make sure the starting area is free of dirt, sand, gavel, or other loose debris
Always wear a heavy leather glove when starting the engine.
Turn on the radio system and check the throttle operation and position.
Have someone (with eye protection) firmly hold the plane.
1. Close the choke completely.
2. Open the throttle to approximately 1/8 position.
3. Turn on the ignition. ALWAYS BE PREPARED FOR THE ENGINE TO START ON ANY FLIP OF
THE PROP, whether the ignition switch is on or off! Flipping the prop with the ignition off may flood
the engine.
4. Give the prop a quick, firm, flip counter clockwise. Follow through quickly as you flip the prop so
your hand swings out of the props path. Repeat until the engine fires or "pops". Flip the prop one
more time.
5. Open the choke.
6. Set throttle to idle position. (carburetor butterfly plate just slightly open)
7. Flip the prop again until the engine fires and runs.
8. Let the engine warm up for 15 to 20 seconds before advancing the throttle.
The engine may not need to be choked if the engine is re-started shortly after the previous run.
If the engine becomes flooded, removing or "pinching" the fuel line while flipping the prop quickly will
help to dry things out. The spark plug can also be removed to speed the process.
Needle Adjustments
The needle farthest to the rear of the engine is the "High End" needle. The needle closest to the
engine is the "Low End" needle. Turning the needles clockwise "leans" the fuel mixture. Turning
the needles counter-clockwise "richens" the fuel mixture.
Settings will vary with altitude, temperature, humidity, fuel, carburetor variances, etc. A general
starting point is: 1-1/2 open on the Low needle, 1-1/2 open on the High needle.
Adjust the High needle to peak rpm. A tachometer is a great help, but remember that the peak
RPM usually drops a little bit after every start due to heat build up. Don't lean the mixture any more
than necessary. If the rpm steadily drops at full throttle or fades on long vertical maneuvers, the
engine is too lean and is over heating.
Adjust the Low needle until you achieve a smooth idle and a reliable transition to high throttle.
Generally if the engine "stutters" or "coughs" in the mid range or when the throttle is advanced, the
Low end is too rich and possibly even the High needle. If the engine dies quickly or sags during
transition, the Low end is probably lean. Note: The low needle flows a small amount of fuel through
the entire RPM range. Adjusting the low needle can have a slight effect on the higher RPM range.
While it is possible for the DA85 to idle below 1,000 RPM, an idle setting around 1,500 RPM insures
a more reliable idle and throttle transition. Prop size has a big effect on the idle characteristics.
Set the High needle only slightly rich during break-in. Operating the engine overly rich not only
reduces power, it creates other problems such as poor transition, pre-mature carbon build-up,
fouled plugs, excessive exhaust residue, sticking rings, and overall rough running.
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