This refers to the steering geometry. On many karts, when there is steering input, the outer wheel will turn less than the inside wheel. The amount the outer wheel is turned versus the amount of steering angle on the inner inner wheel can be a valuable tuning aid. When ackerman is changed, the entire front end is changed and alignment needs to be addressed.
This is a typically plastic apparatus that encloses the intake of the carburetor. This device sometimes also encloses an air filter. The main purpose is to reduce the noise of the engine.