Hi all,

My DA100 has started to act up at idle. When I chop the throttle, it will go to a low idle, then slowly speed up. It's gotten to be a real problem for IMAC. If I set the throttle trim for a slow idle, it'll deadstick at the top of a hammer. If I set the throttle trim up a few notches, it idles too fast to spin.

People say it must be too lean on the low end, but I've been richening it, and the low needle is out past where it should be. I checked the carb and reed block and they're tight. Any ideas?

Thanks

Mark

Throttle servo or throttle linkage are a possibility.

An air leak in some part of the engine.

It does seem to be fuel system related. You might take the reed block off and check to see that the reeds are seating properly. Get a carburetor kit and overhaul it. Just replace the parts that are easy to get to, including the screen. While you have it open spray it out with some carburetor cleaner. Inspect the carb mounting block for cracks.

I have cleaned and overhauled the carb recently. The screen is clean. Everything is tight. The crankcase halves are tight and the outside of the motor is dry.

I tried to remove the reed block, but it's really stuck to the crankcase. It looks like it has a good seal all around, and I didn't see the point in ripping it off and then having to re-seal it. Maybe I should. Does anyone know what kind of sealant DA uses?

I replaced the throttle servo and richened the low end a bit more. I may have to just pull the throttle back more slowly when I do my hammers.

Thanks!

Hi!
When an engine speeds up after throttle down it is too lean on the idle needle.
Does it behave this way in the pits too or is it only in the air??

I wouldn't fly until you can get the idle to be constant. Like jaka and others have said, sounds lean. Keep richening to see if that stops it. Don't worry about how far you go out on the low needle. If it fixes it it fixes it no matter where it is. BUT if no matter what you do to the low needle, it still doesn't fix it, then you need to look for an air leak. Try to go as rich as possible on the low needle to get the idle constant. It's easy to try and won't hurt anything.

Hi Mark, these are all good suggestions. I've had these problems and found, servo,linkage, low needle, carb, heat, and bad gas (water=heat) were my problems. Yours seems like fuel delivery.

If you can give DA a call and get some support, you will most surly resolve you problem this way.

DA 520.722.0607

HTH

Joe

It does it in the air and on the ground. I'll try richening it way up on the low end the next time I fly it.