It adjusts the slide inside the carb, linkage isn't in a bind, but both in terms of the motor revs and the truck trying to move forward on it's own it does absolutely nothing. Tried three full turns, going to extremes trying to get it to do something and revs never change truck will still creep forwards but then it will slowly die. It's my first nitro, I don't know how much is too much fuel out of the exhaust but the entire back end of the car is completely covered in unburnt fuel, Literally from the back of the fuel tank all the way to the plastic chrome bumper. That seems excessive to me like it's running stupid rich. If I start leaning it out from factory settings it will just start dying if you give it any throttle. I've only really adjusted the LSN to get the idle right and to tune the acceleration from a dead stop. Even that though seems to drift. I'll get it where it sounds good, good idle speed, doesn't roll forwards and then a few passes it will bump up in idle speed and start rolling or it will sound like it developed a deviated septum, idle will start dropping and it will start dying. I honestly think something is wrong with the engine if conventional wisdom is factory settings are supposed to be rich for break in and I'm having to go the opposite way.

Traxxas support was pretty terrible. First guy asked my name and then just put the call on hold indefinitely after getting my name, waited like 5-6 minutes. Second guy at least sent me a replacement glow plug and said it sounded rich and just hung up. Fuel was suggested to me by my LHS, I figured Traxxas truck, Traxxas fuel should work. I've heard bad stuff about them and the only reason I went with them was I wanted a truck because I run mostly on grass and buggies from what I've seen and heard just don't run good on grass. More for sandy or dirt tracks. Maybe I shoulda went HPI but good luck finding it locally and I have yet to find someone who retails them online.