Observation

Most of the candidates who attempted this question were able to provide the required responses to parts (a) and (b) of the question.  The only difficult part was part (c) of the question.  The required response to this part is:

(c)        Merits of air-cool engine include:

it is simple in construction;

it has light weight;

it is cheaper;

it does not freeze;

it is free from leakage;

it warms up quickly;

air is readily available;

there is not topping up of the cooling system.

 

Merits of water-cool engine include

 

there is reduced mechanical noise;

temperature of various engine parts are more uniform;

improved thermal efficiency;

cylinders can be placed closer together or it is more compact;

the engine can operate under critical condition.