QUOTE=Awesome;1491975 Here's my story with lockout with the A9. Happened on the ground. , in my back yard as a matter of fact.
<snip></snip>I checked for loose connections , but found none. Battery for RX had been tested on a West Mountain CBA before i fitted it to the model , so no voltage problems.
Thought maybe i had a dud ignition so i fitted a RCEXL ignition instead of the MLD ignition. Problem solved!
No more lockout , range tests further than i like to walk. Have been flying it for over 6 months with zero radio problems , apart from a reversed kill switch channel on Aux1 afer the latest update.
Whats more is when i bought the MLD 35 , i actually bought two of them , one for a fellow club member who runs a JR radio. Guess what , with the MLD fitted his JR would go in and out of lockout with engine running range test!
He rang me to tell me of his problem and i suggested he fit a RCEXL igniton and try again. Fixed the problem completely.
I sent both ignitions back to the shop we bought the engines from to China , only to have the same ignitions posted back i had sent in the first place. (i marked the cases , call me an untrusting person) They told me they sent new ones.
I refitted the ignition to my engine and tested it again. Guess what , locked A9 again!
<snip></snip>Thanks for reading , Leon. [QUOTE]

How many of the others are using standard non resistor type spark plugs?
Sparkplugs can cause interference with all known receivers.
A resistor spark plug has been recommended for all petrol engines used in RC models for past 30+ years. I would not fly around any one using a non resistor type plug and most concerned with any manufacturer who would supply motors intended for RC use without a resistor plug or lead with inbuilt resistor cap installed. I understood that in USA at least, for past say 20 years, it was not legal to sell petrol motors for use unless they were properly fitted to prevent rf emissions. This to prevent interference problems with TV, radio and other electronic reception and applied to all motor mowers, Weed Trimmers, chainsaw engines and others intended for domestic use within US market and as also sold here.

BME: "SPARK PLUGS:
We recommend using Champion RCJ7Y, Bosch WSR6F, or NGK BPMR6A spark plugs. The "R" indicates that it is a resistor plug. A resistor plug is required in order to prevent radio interference. If an alternate plug is to be used, it must be a resistor plug of the same heat range and reach and the RCJ7Y. The small 10mm (CM6) and ME8 spark plugs are not resistor plugs and therefore require special spark plug leads with metal caps to prevent RF leakage that will cause radio interference. If you need to use the smaller non-resistive plugs, contact BME or the ignition manufacturer for additional details and special ignition components."

Quadra have always noted "R" plugs only, as attached, similar with the Zenoah manual and other manual/instructions held, typically:.
" If you replace the spark plug on the motor, make sure to get the same type that was there in the first place, at least make sure that it is a "Resistor" type plug."

with more sub Section "Glitches & Jitter in Receiver, Servo & ESC - causes and cures " under
"Radio Systems, Accessories, Alterations and FAQ." at:
Alan's Hobby, Model & RC FAQ Web Links

20Jun11 added post #3900:
There are two types of CM6 plug, one is standard NGK CM6 spark plug but the one which should be used is the NGK CMR6A "R" resistor plug to prevent RFI.
<snip></snip>In this day and age, I had not thought to ask/suggest the question earlier in the thread as I was of the belief that it was "given" that a "R" plug or pictured post #4868 DLE Thread was in use, and was interested in how many users who had problems had actually checked their plug and cap, given also
. "Whats more is when i bought the MLD 35 , i actually bought two of them , one for a fellow club member who runs a JR radio. Guess what , with the MLD fitted his JR would go in and out of lockout with engine running range test!" RFI effects all brands.
. " So i removed the CM6 plug cap and found the problem. No resistor fitted to the H/T lead! Ordered a new CM6 plug cap kit , fitted the resistor and put it back on the engine. Range tests just as good as the RCEXL does now. "
Also covered Spectra 2Ghz Module - Optima Receiver - Range Test Procedures
. e). NB: It is imperative that all engine/motor equipped models are tested both with and without the engine/motor running whilst throttle is moved up and down both slowly and rapidly through the full throttle range to determine if there is any interference caused by the ignition system (frequent cause of problems) or motor/ESC and if any vibration problems from bent shafts or bad propeller. {RFI occurs at different throttle settings on petrol/ ignition engines}

see also sub sections:
"Glitches & Jitter in Receiver, Servo & ESC - Causes and Cures "
"Receiver Operating Range, Range Test & Range Problem Solving"
"Petrol engines, carburettors and ignition systems"
under
Alan's Hobby, Model & RC FAQ Web Links

Alan T.