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DA100-Ran perfect until today-went rough midflight

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Old 12-04-2011, 03:45 PM
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flyerdave
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Default DA100-Ran perfect until today-went rough midflight

DA100 on my 35% aeroworks has always run great and today was no exception until the last flight. I had taken off and was at about 90% throttle, all of a sudden, it started running really rough and lost power, almost like it was on one cylinder. When I dropped the throttle, I had enough power to land and it smoothed out. Got it back on the ground and running it up anything abov about 1/3 throttle, it would cut out and run rough, anything 1/3 throttle and below smoothes out.
Could this be the ignition or a plug going bad?
If anyone can give me an idea what to check before I send this thing back to DA, I would appreciate it.
Thanks
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Old 12-04-2011, 04:01 PM
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Default RE: DA100-Ran perfect until today-went rough midflight

Bad reed?

Ignition battery?

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Old 12-04-2011, 04:34 PM
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Default RE: DA100-Ran perfect until today-went rough midflight

Thanks w8ye,
I just pulled the plane out of the trailer, set it up, started just like always and ran it up several times. It is running as good now as it ever has. I have not recharged or changed the ignition battery. It is a 2300 ma sub c nicad 4.8 volt.I will change out the ignition battery just to rule out that possibility.Is it possible that a bad reed could be something that comes and goes?
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Old 12-04-2011, 04:46 PM
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Default RE: DA100-Ran perfect until today-went rough midflight

Not usually but to en-richen the mixture will sometimes mask a minor reed problem

In cold air, our engines sometimes need to be enriched, mixture wise, because the cold air is denser.

There could be one of several different problems?

I fought this a month ago with a DLE 55. Through substitution of carbs and ignitions, it came down to the reed block. Apparently the plastic will distort after a few runs and one corner of a reed will not seat against the body or block. The reed block can usually be re-leveled and saved?

If all else fails to change performance, then look at the reeds with a light on the other side of the block to check it out?
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Old 12-04-2011, 04:52 PM
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Default RE: DA100-Ran perfect until today-went rough midflight

I'm predicting: "Intermittent ignition problem - may be heat related"

This has happened to me. The ignition module works for a while but after it gets to a certain temperature, one half of it starts to fail. So you get intermittent or no spark on one cylinder. Once it cools off, it runs fine again until it gets warmed up. Mine was pretty consistently around the 12 minute mark on the flight timer. Unfortunately, the only way to know for sure is to buy a new ignition system and try it out. If you've guessed wrong, you now have a spare ignition you can carry around with you.
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Old 12-04-2011, 04:57 PM
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Default RE: DA100-Ran perfect until today-went rough midflight

The DA engines are the most popular by far at the local flying field. No one works on them, they send them back to DA.
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Old 12-04-2011, 05:15 PM
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Default RE: DA100-Ran perfect until today-went rough midflight




ORIGINAL: w8ye

The DA engines are the most popular by far at the local flying field. No one works on them, they send them back to DA.
Isn't that the truth, all other brands ofengines can be repaired by the owner, DA'sgot to go back?
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Old 12-04-2011, 05:38 PM
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Default RE: DA100-Ran perfect until today-went rough midflight


ORIGINAL: Tony Hallo




ORIGINAL: w8ye

The DA engines are the most popular by far at the local flying field. No one works on them, they send them back to DA.
Isn't that the truth, all other brands of engines can be repaired by the owner, DA's got to go back?

i remember when i was much greener, i used to send off my glow engines to have the bearings replaced... it would run me about 70(2 stroke) -$90(4 stroke) ...BJ made some good money off me... not any more.... The RCU community has really helped me out... you tube as well
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Old 12-04-2011, 05:43 PM
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Default RE: DA100-Ran perfect until today-went rough midflight

If I understand right, there is no repair for a bad ignition, just order a new one. Is this correct? Are there any aftermarket ignitions for the DA100 or can they only be purchased from DA?
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Old 12-04-2011, 06:01 PM
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Default RE: DA100-Ran perfect until today-went rough midflight

Some people adapt a RCEXL to them. DA will not like it?
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Old 12-04-2011, 07:41 PM
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Default RE: DA100-Ran perfect until today-went rough midflight

RCEXL ignition is not a direct replacement. The sensor will have to be installed differently. This usually means drilling and tapping the case up on the nose. Does the ignition have the original Sermos Power Pole connector on the voltage input side? If so that is the first thing I would look at. The wire just at the crip has a way of fracturing due to the vibration. Lots of guys replace that connector before install. I would also be looking at the battery. If that checks out, look inside your plug caps. They should be clean, any dirt should be cleaned out with alcohol. If they are loose fitting on the plug take off the metal ring and and squuze it to cloce it slightly. Look at the plugs. The gap should be about .015. Any more and the ignition may not have enough to bridge the gap.
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Old 12-04-2011, 07:58 PM
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Default RE: DA100-Ran perfect until today-went rough midflight

RC EXL ignitions now come with a sensor mount that requires no drilling, the legs are slotted way longer...You have to check the magnet in the hub before you put the sensor in the bracket...the south pole of the magnet triggers the sensor..you can turn the sensor over in the bracket if the North pole is facing up...
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Old 12-04-2011, 09:34 PM
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Default RE: DA100-Ran perfect until today-went rough midflight


ORIGINAL: Antique

RC EXL ignitions now come with a sensor mount that requires no drilling, the legs are slotted way longer...You have to check the magnet in the hub before you put the sensor in the bracket...the south pole of the magnet triggers the sensor..you can turn the sensor over in the bracket if the North pole is facing up...
I tried to use the new RCEXL hall switch mount on a DA 50.Could not get timing set and use both bolts. This was the new mount with four longer slots. I just used our universal clamp and a brass channel solored onto it to hold the hall sensor.On RCEXL and most engines the letter or number side of the hall chip goes towred the magnet . On DA and Some 3-W the dot side toward the magnet. I no this is what you said.
Did you get package one Ign has no timing control. Try the one that mentions hand start,has new pic 16 processor that XU L used on our ignition. I have many Pic timing boards left over.
Grumpy no ten.
BC used to be BCCHI no more.
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Old 12-05-2011, 04:34 AM
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Default RE: DA100-Ran perfect until today-went rough midflight

One last thing before I change ignition batteries. I've always used a 4.8 volt instead of 6.0 for ignition because I didn't want to chance cooking the ignition. Would the DA ignition do better with the 6.0 volt or should that have no bearing on the above problem. I have some NiMH 2700ma 6.0 volt batteries that I have been reluctant to attach to an ignition.
Thanks
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Old 12-05-2011, 05:06 AM
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Default RE: DA100-Ran perfect until today-went rough midflight

I doubt that is your problem unless there's a problem with the battery itself.
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Old 12-05-2011, 05:06 AM
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Default RE: DA100-Ran perfect until today-went rough midflight

You have to be careful here... read up on that module... some newer ones will work on 6v older ones it will fry. There should be something on the label.

ORIGINAL: flyerdave

One last thing before I change ignition batteries. I've always used a 4.8 volt instead of 6.0 for ignition because I didn't want to chance cooking the ignition. Would the DA ignition do better with the 6.0 volt or should that have no bearing on the above problem. I have some NiMH 2700ma 6.0 volt batteries that I have been reluctant to attach to an ignition.
Thanks
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Old 12-05-2011, 07:34 AM
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Default RE: DA100-Ran perfect until today-went rough midflight

I would not change the way you have your ignition set up. 4.8 volts up to 6 volts (do not use a 6 volt battery on ignition when fully charged it will go above 6 volts and can damage the ignition module)is fine, the way you have been doing it. Although it may be ignition related, I would check a couple of things first. You say that when you pulled the throttle back the engine smoothed out. Correct? If so I would check some simple things first. Here is a list I think might be of some help and also a question or 2 thrown in.

1. How old is your fuel tubing?
2. Do you use an inline filter?
3. I suspect that you might have possibly picked up some debris in the carb or the engine went lean due to temps. (I lean more toward the debris as you ran some flights before).
4. Is your clunk connected?
5. Remove the carb from the bottom of the engine and disassemble until you can see the screens. Take a magnifying glass and look at the screens. If you see a white powdery residue, the carb is dirty and needs a good cleaning. You can go to your chain saw or lawn mower shop and buy an overhaul kit for all Walboro carbs for about 7 to 15 dollars.
6. Now is a good time to replace all your fuel tubing and ensure there are no leaks between the carb and the carb block.
7. Since it is cold you might want to richen up the needles a tad. If the engine went lean and the cylinder head got too warm it will stumble.

I do not want to start a debate on oil but I have to ask what mix you are running. Notice I said mix not brand. I know a ton of guys who run 100:1 however I do not recommend it. If your comfortable with that ratio, more power to you. However if you are not flying for competition I would run 32:1 at all times.

Hope this helps. If you need more assistance let me know. I can be reached on my personal e-mail at willig@yahoo.com

Regards
Glenn Williams
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Old 12-05-2011, 08:34 AM
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Default RE: DA100-Ran perfect until today-went rough midflight

Inspect the tank stopper too. I had one that acted up after a few minutes, turned out it was sucking air when the tank level got below the stopper.
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Old 12-05-2011, 08:59 AM
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Default RE: DA100-Ran perfect until today-went rough midflight


ORIGINAL: BarracudaHockey

Inspect the tank stopper too. I had one that acted up after a few minutes, turned out it was sucking air when the tank level got below the stopper.
I experirnced this. There has a hairline crack in the brass tubing inside the stopper.

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Old 12-05-2011, 09:06 AM
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Default RE: DA100-Ran perfect until today-went rough midflight

My idea is the same as previous posters. Looks like the fuel system went sour. Symptoms are typical for a clogged internal fuel screen, or dirty fuel admission bore (under the needle valve)
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Old 12-05-2011, 02:36 PM
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Default RE: DA100-Ran perfect until today-went rough midflight

if it was a dirty screen or trash under the needle it would do it all time,not run perfect after he got it home,,sounds like a battery problem would be the best place to start,,remember most things mechanical don't come and go like you described .as for the voltage don't ever run a da ignition over about 5.2 volts,it will shorten the life span fast
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Old 12-05-2011, 03:12 PM
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Default RE: DA100-Ran perfect until today-went rough midflight

Negative on that. If you have a dirty/clogged carb, it will and can cause a lean condition due to restrictted fuel flow. This will over time get worse. You will continually have to enrichen your carb to over come the screens becoming clogged. Regards Glenn Williams
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Old 12-05-2011, 03:27 PM
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Default RE: DA100-Ran perfect until today-went rough midflight

I am on my i-phone and let clarify my last post. The engine will run fine with a dirty carb, until it gets some heat in the cylinders under flight loads. Once the cylinders or cylinder gets too hot the condition wll re- occur until the carb or affected fuel component is cleaned/repaired. Bottom line it sounds like the OP,s engine got too lean and stumbled inflight.
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Old 12-05-2011, 03:50 PM
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Default RE: DA100-Ran perfect until today-went rough midflight

Tell you how to solve the problem sell me the motor say $150 take t money add a few more dollars to it and buy a 3w
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Old 12-05-2011, 04:39 PM
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Default RE: DA100-Ran perfect until today-went rough midflight


ORIGINAL: BarracudaHockey

Inspect the tank stopper too. I had one that acted up after a few minutes, turned out it was sucking air when the tank level got below the stopper.

This sounds like something good to check. perhaps with a vacuum pump and gauge. pull a vacuum on the tank and see if it leaks down. Or just change it anyway for $6.

I like the idea of a fuel starvation condition. I think a stuck reed valve would do it too. I would personally say the reed valve is less likely than tank issues or ignition issues.
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