I'm fairly new to nitro and recently purchased the AD2. I installed a Novarossi TOP .12 engine and during the break in session a couple things happened.

1. The engine idles "inconsistently" revs up...then revs down. Is this normal?

2. Without the foam filter it runs but if I add the foam filter while its running, it quickly stalls. Lack of air maybe?

3. So I ran it on my back yard grass in circles (checking temp) and it seemed to run smoothly, sounded good, but I still couldn't add the foam filter?? Hmm...after a few more circles i noticed the diff started spinning. Spurr moving but wheels werent. After I pulled the gearbox I out I found that I shredded the yellowish idler gear inside. How did this happened? I've heard of diff gears melting but the idler gear? What could cause this and what can I do to provent it from happening again?

Any advise will be appreciated,

Novice Nitro Victim

If you did breakin and tuning without the filter then I'm sure your needles are too rich, since there's going to be more air flow without the filter. And when you refer to the "foam filter," are you talking about a foam pre-filter, or have you been running with no filter at all? If the later is the case then slap that thing on, ziptie it and fiddle with the thing as long as it takes to figure out the carb settings to get it running. Otherwise you're running a very great risk with an engine that's not exactly cheap... if you haven't already shortened your piston/sleeve life.

Yes, referring to the pre foam filter. If its too rich, I'll try that adjustment today. First will add it back on and go from there. What about shredding the yellowish idler gear inside? Has this happened to anyone?