This video shows you how to tune the ACME attacker 1/8th scale nitro engine buggy. Use the high end valve and the idle speed screw as show in the film. Turn the engine and get it to the operating temperature and drive round to the see how the car performs. If the acceleration is sluggish then the low end valve should be adjusted. If the engine is having too much RPM then the idle speed should be reduced using the idle speed screw. If the engine bogs down and makes noise on full throttle and is quite sluggish then the HSN is lean and should be richened out using the high end needle. The video then shows examples of all these issues and exactly what steps should be performed to correct them.