KCSE 2014 Power Mechanics Paper 2 Questions with Marking Scheme

QUESTIONS

STATION 1
In the space below, sketch in good proportion a sectional view of a sparking plug, Label four parts.(10 marks)

STATION 2
Using the tools, equipment and materials provided, fabricate the support bracket shown in figure 2. (10 marks)

STATION 3
Identify the items labelled A to E. For each item:

1. state the material it is made of;
2. name its use in a motor vehicle.(10 marks)

Complete Table 1
Table 1

STATION 4
On the piston provided, perform the following tasks:

1. measure the side clearance of the piston ring:
2. remove the ring from the piston;
3. measure the free gap of the ring;
4. measure the working gap of the ring;
5. fit the ring back into the piston.(10 marks)

(Let the examiner check your work)

STATION 5
Using the tools and materials provided, connect the ignition circuit of a motor vehicle using one sparking plug (10 marks)
(Let the examiner check your work)

STATION 6
Identify the parts labelled K, L, M, N and O. Name the vehicle system in which each part is used. For each part, identify one defect and state its effect on vehicle performance.
Complete Table 2
Table 2

(10 marks)

STATION 7
On the gas welding equipment provided,

1. Identify the parts labelled P, Q, R, S and T.(2¹/₂ marks)
   

   PART	NAME
   P
   Q
   R
   S
   T

2. Without adjusting the regular pressure, light the equipment and set the torch to obtain an oxidising flame.(6¹/₂ marks)
3. Shut down the gas equipment.(1 mark)

STATION 8

1. For the single cylinder engine provided, measure and record the following:
   1. bore
   2. stroke(2 marks)
2. Calculate the compression ratio of the engine if the clearance volume is taken to be 10% of the displacement volume.(8 marks)

STATION 9
On the multicylinder engine provided;

1. remove the fanbelt;
2. identify two defects on the fanbelt and state one possible cause of each defect;
3. state the correct remedy for each defect:
4. re-fit the fanbelt.(10 marks)

STATION 10
On the battery provided, perform the following operations:

1. measure and record the specific gravity and battery voltage of each cell in Table 3. (Take cell number 1 to be next to the positive terminal)
   Table 3
   

   CELL NUMBER	SPECIFIC GRAVITY	BATTERY VOLTAGE
   1
   2
   3
   4
   5
   6

2. Check and comment on the state of:
   1. battery electrolyte level
   2. battery charge (10 marks)