mostly ran my engine in today on my acme condor, couple of questions

it's starts pretty well but rolls along on it's own at about a walking pace and when i put the brake and stop it it stalls, any idea what can be causing this? a friend tried adjusting the idle but it either rolls or stalls.

also when the engine is running without me giving any throttle it sounds quite rattly it quiets down when the throttles on, my mate runs a tamiya nitro thunder and compared to that it seems loud. is this normal?

thanks