Auto Electrical Works Paper 2, WASSCE (SC), 2018

Question 2

 

(a) State one function of each of the following in the starting system of a motor vehicle:
            (i)         battery;
            (ii)        flywheel;
            (iii)       solenoid.
(b) Table 2 contains symptoms of faults in the starting system of a motor vehicle.
                                                                        Table 2


Symptom of fault

Possible causes

Remedies

Starter motor cranks slowly

(i)

(i)

(ii)

(ii)

Starter spins but does not crank engine

(i)

(i)

(ii)

(ii)

Noisy starter motor

(i)

(i)

(ii)

(ii)

Complete Table 2 by stating two possible causes and remedies for each symptom.

Observation

 

(a) (i) The battery supplies d.c. current into the system.         

(ii) The flywheel links the pinion to crank the engine.                                       
(iii) The solenoid acts as relay circuit/connects and disconnects the pinion.  

               

              (b)                                                      Table 2


Symptom of fault

Possible causes

Remedies

Starter motor cranks slowly

Low battery voltage

Charge/replace battery

Loose/corroded/broken connection

Clean/repair/replace connection/terminals

Cable size too small

Replace with proper size cable

Internal starter motor problems/faulty starter motor

Replace/overhaul starter

Engine oil too thick/high viscosity

Use oil of proper viscosity

Faulty shaft

Replace shaft

Ignition timing too far advanced

Set timing to specifications

Starter spins but does not crank engine

Defective plunger overrunning clutch

Replace defective part

Broken starter drive gear

Replace drive gear

Broken flywheel teeth

Replace flywheel

Noisy starter motor

Loose starter mounting

Tighten mounting bolts

Worn starter drive gear/flywheel teeth

Replace starter/flywheel

Worn starter bushing

Replace/overhaul starter

Excessive vibration

Replace starter/flywheel

                                                                          
Candidates were required to state possible causes of the symptoms of faults listed in the Table and their corresponding remedies. Only a few candidates were able to state the matching remedies to causes stated.