OK heres one for you, DA 100, starts fine but will not power up to full throttle. Pulled both plugs and flipped checked to see if I was getting spark. Initially only the rt pluged fired. I then swapped plug positions and flipped checked and both plugs had spark.

Went back out to the field this weekend and the same thing happend. engine starts but will not advance and lacks power.

I temped the heads with my Rayteck and the left cyl is at 100- and the rt is at 140..... at Idle.....

Do I have preliminary IGN failure.....?????

Spectre1

What about the needles?

Engine was running just fine I havent touched the needle valves all summer long.....

Yes, You may have ignition problem. My DA ignition exhibited this similar behavior when it was three months old. Was replaced under warranty and all has been good since. My symptoms were that the engine would quit in the air, but would then restart. Sometimes after the restart it would run crappy. (like on one cylinder). I chased this problem around for a while (changing tanks, resetting needle valves. etc.). Finally the ignition would only fire one one cylinder ALL the time. At this point it was easy to diagnose by swapping the ignition wires like you did.

Thats my uneducated guess, Ill call DA in the morning and see what they have to say.

While you may have an ignition problem it should be obvious if your running on one cylinder. The temp gun directed to the exhaust outlet will solve this one.

The needles may prove to be out of tune, it would be simple to note there exisiting location, return them to factory recommendations and or re-tune the engine. This will at the very least eleminate a variable.

I'd also look at the carb fuel inlet, under the plate is a screen/filter.

I have had this exact same problem and have jsut had my ignition swapped under warranty. The firs tsign of tyhe fault was a severe drop in power of the engine, by 500rpm+. Then it would only start on one cylinder, was fine in the air, but rpm would hunt up and down. Finally one cylinder died altogether. I have been informed that it is the light and delicate coils used to generate the HT for ignition. They are possibly sensitive to battery overvoltage fresh of the charge, or by being left in a charged state and then discharged in an abnormal fashion (ie accidental short while diagnosing faults etc). I have also been told not to use a 5-cell pack with the ignition system as of course this is producing 7+v fresh off the charge which is way over the rated voltage. So im now using a 3000 4.8v pack and it seems fine. Other option is to use LiPo or 5-cells with regulator, one wonders why DA dont install one themselves?

I've had my DAs for over 2.5 years and I just found a quote in the manual last week; it says you are supposed to flip the prop over a couple times after flying to discharge the ignition box. Neat.

Not that it will help you now, but good to know.