ORIGINAL: Elite_Tux487
It sounds like it is WAY to rich if you see fuel spewing out of the exhaust. Try leaning out the highspeed needle. Also that isn't the best way to break in a new engine despite what the manufacture says. If you decide to get another nitro vehicle or a new engine use the "heat cycling method"
when you first get it running it should spit fuel/oil out the exhaust because the factory sets them rich for breakin.
And of course what would the manufacturer of the engine know about how to break them in??? they only spend millions of dollars on R&D to make sure that things work right. First and foremost if you are NEW to Nitro you SHOULD follow the manufacturers guidelines UNTIL you have enough experience to be able to do something like heat cycling to break in your motor.
Also, IF there are people in your area that do R/C go talk to them and have them watch you and your car/truck and they can help you get it tuned better than trying to figure out which way you should do it from 500 posts on a message board.
As one person I listen to on the radio on the weekends says it: "You need to get a pair of eyes on it, to really be able to diagnose the problem".