Observation

Some of the candidates couldn’t provide adequate answers to question 5(a) and 5(b). The solutions to the poorly answered questions are given below

(a)        Demerits of an air-cooled engine

• It runs at higher temperature and therefore prone to overheating
• Very noisy in operation
• Difficulty in cooling all the cylinders equally
• Spacing of cylinder must be sufficiently wide enough
• It is not ideal for heavy duty engine or suitable only for small engine
• It is difficult to arrange interior heating or cooling
• It requires a larger fan
• Large surface area is required to dissipate the heat
• It is less efficient

(b)        Defects in friction clutches that cause  clutch slip

• Worn lining or clutch wear
• Binding pedal mechanism
• Greasy facings or lubricant on the lining(s)
• Incorrect pedal adjustment
• Inadequate free play or pedal not returning well
• Weak pressure springs
• Scored faces of flywheel
• Incorrect refitted floor board or carpet
• Scored faces of pressure plate
• Excessive heat