Basic Gas Engine RF Trouble Shooting:

What type of ignition is it? Does the plug lead have braided shielding on the outside of the plug cable? If not, does it have a separate ground strap?

If using a separate ground strap how and where is it secured?

What kind of spark plug does the engine use? Standard but shorter automotive plug or NGK CM-6 type? If it's a standard type plug make certain it's a resistor plug. It will have an "R" in the part number.

Is the spark plug the original from an "eastern" source? if so, replace it with new from an established manufacturer.

Are the wire contacts tight to the top of the plug inside the cap?

Is the plug wire in good condition with no obvious breaks in the wire or plug cap boot?

Does the plug cap tightly secure to the plug on the outside?

Is the ignition battery (and wire!) in good condition and well charged?

Are you using any servo extensions on the battery, ignition switch, or ignition wiring? If so, check them to make sure they are clean, tight, and secured at all connectors with perfect continuity.

Do you have metal to metal contact at the carb throttle lever? If so, replce that connection with something that has plastic or nylon between the control rod and the carb lever. With ell installedcomonents a good ignition will handle just about any type of control rod used with no problems. That was not true with "yesterday's" ignitions.

Do you have any loose nuts and bolts that may be rattled by engine vibration? If so, tighten and use Locktite to prevent loosening.

Is the receiver crystal secured in the receiver? If not, use a piece of tape over the crystal to hold it in place.

Is the ignition switch new and of good quality or is it old, used, or from a budget after market manufacturer?

Were any of the servo extensions, switches, servos, batteries, or receiver used in another plane that crashed? Were they manufacturer checked after the crash? If so and if not get rid of them for something new.

Are any of the servo extensions old, having been used in one or more other planes? Junk them and buy new from a quality manufacturer, not a budget house.

Does the receiver antenna run back inside the fuselage next to rudder and elevator servo wires or pull-pull cables? If so separate the antannea away from those by as much distance as possible.

Are the engine mounting bolts tight? Loose causes rf as the engine shakes.

Now check every nut, washer and screw on the plane to make sure that none of them may be rattling making tiny metal to metal contact noises.

Are you using metal control clevises with metal control horns? If so and they can't be secured with a screw and a nut change to something else.

Every one of the above are basic, standard, everyday checks that should be done when setting up a plane that will use a gas engine to help eliminate the possibility of RF prior to the first flight. You'll note that many of them do not relate to the ignition in any way. This is because most so called "ignition" RF problems are not ignition induced at all, but vibration induced. The ignition is always blamed for them, but generally is not the problem.