Well this nothing within 12" used to be a "no way, no how" install, but that's pretty much long gone unless you're running something that's an older engine with a magneto or something or a conversion.</p>

Lots of ARF's come with a servo cutout for the throttle servo in the engine box and I've had no difficulty with any of mine mounted that way.</p>

I would where possible, keep the electronics other than the ignition module as far away as possible if you can't get 12" away just as a matter of course. Make sure you don't use metal to metal connections on the linkage and do the ground range checks including with the engine running. You don't say what radio, but the 2.4GHz systems are more resistant than 72MHz systems to interference from most of the possible causes except loose sparks intended for the sparkplug and those will give you headaches with any system. Such things as a non resistor plug installed when it's supposed to be a resitor type, cut shielding on the sparkplug wire, poor contact with the sparkplug electrode and so on can cause grief. Also some engines require a ground lead.</p>

Your ground range checks should tell you if what you've installed is going to work, but there are certainly other places where you can pick up interference and/or radio problems so don't just pay attention to the engine related stuff at the expense of the rest of the setup.</p>