This is the first Nitro I try to run. I have all electric before this one. I bought older model used traxxas trx .15 nitro sport. I could not get it started. I bought all new seal for carb. and try again and no luck it would no stay running. I play with the H/L needle still not luck. So I took apart the engine. I read if you can push the piston pass the piston sleeve it no good and you would need to buy new parts. Also can you break a engine in on 10% fuel with some run after oil or do I need to buy some 20% fuel. hope I can get some help thanks