nitro r/c car engine locked up. HELP!?

I was driving my r/c car when a noise that sounded like dirt got in and the engine stoped.the pull starter won't even pull! i think dirt got in through the air filter. don't know how to fix it. the engine is stuck.

>.::pDaMaN::.<
Never mind, a rock was just stuck under the fly wheel. so it's all good

those little engines are junk once anything gets into them I know i used to be in the hobby for 10 years. You need to pull the back plate off the engine and look inside to see if the connecting rod broke if it did than you need to get a new engine. The next place I would look it the cylinder take the head off and look in to the cylinder if you see score marks on it than the engine it toast. Those engines only have two assembly's that move the crank shaft assembly (crank and bearings) and the reciprocating assembly (piston connecting rod and wrist pin) so their is not that much that can go wrong hear. R/C cars are not complicated to work on. Also in the future make shore that their is a faint smoke trail behind the car when it passes you the engine may have also seized up from over heating and running lean. Those engines have to be run a little on the rich side.