In-Line Fuel Filter – For whatever reason, most manufactures do NOT include a fuel filter. Though this is one of if not the easiest way for dirt to enter your engine. How many people refill their tanks in a perfectly clean environment? I know I dont…usually its somewhere where the dirt is already flying in the air from bashing, the truck is already covered in dust, dirt, mud or whatever. So when dirt gets in the tank it goes straight to the heart of your R/C…the engine.