I recently purchased a Patty Wagstaff Extra 300 with a Turnigy 50HP engine. When running the engine at idle or slightly above, both elevators go full up deflection and flutter. However, as the throttle is advanced the elevators act normally. No other servos are affected, just the two elevator servos. I changed everything, i.e., new Spektrum 2.4 receiver, new switches, wiring, batteries, servo reverser harness, etc.. A radio range check without the engine running was good to over 120+ feet without a flutter or loss of control. However, with the engine running the elevators again fluttered and went to full up deflection just standing next to the airplane. I put two new servos on the elevator, but had the same result. The Turnigy is my first experience with an ignition engine and know little about what happens when an ignition module starts to go bad, e.g., does it cause interference and would it be localized to only one radio function such as the elevator? This engine has the original blue ignition system and I read that they have a bad reputation for failure. So if the ignition is my problem, what should I replace it with?
Any suggestion would be much appreciated.

First make sure the plug cap is all the way on the spark plug, They are tight and hard to push on. It should completely cover the hex on the spark plug.

I have seen some post where other people had some of the same problems and put a choke on the battery lead and it solved the problem.

A test you can do that works sometimes is to wrap some tin foil tight around the plug cap and down the plug wire a little way's and see if it stops the problem, This is not a fix but will tell you if you are getting a spark inside the cap.

We sell replacement ignition and they come with a 30 day return so if you get one and it does not solve your problem you can return it for a refund.

Milton

Milton,
Thanks for the quick response. I checked the plug cap, and it was OK. I also tried the foil, but that did not work either. I was told that Spektrum does not work well with chokes...don't know if that is true or not. Anyway, it appears my last resort is to install a new ignition system. I checked your website, but don't know which to order for this engine...let me know and I will order it. If this does not work, I am going to replace the engine with a reliable Zenoah G-45. I have flown them for years without any such problems.
Again, thanks for your help.
Bob

Tell me what spark plug it has and I can tell you what ignition you need.

Or just call me
678 372 7697

Milton