4.5 Possible reasons for over-heating of engine :
1 Low water quantity in radiator or
water tank
2 Ignition starts after specified time
3 Fan belt lose or torn
4 Water jacket jammed
5 Faulty water pump
6 Low quantity of lubricating oil
7 Faulty lube oil pump
8 Broken fan blade
9 Engine operates over load
10 Engine operates at a high speed for
a long time
4.6 Possible reasons for engine vibration :
1 Vibration damper or engine counter-weight are not working
2 Detonation and auto-ignition
3 Main engine bearing, the smaller end bearing of connecting rod, or the thrust
bearing, have become loose.
4.7 Possible reasons for excessive fuel consumption :
1 Frequent starting and stopping uses a lot of fuel
2 Leak in fuel delivery line
3 Leak in fuel tank
4 Air cleaner jammed
5 Engine left in operation unneccessarily
6 Improper valve timing
7 Over loaded engine
4.8 Possible reasons of excessive lubrication consumption :
1 Piston wrongly fitted
2 Piston and connecting rod misaligned
3 Oil ring not placed exactly in oil ring grove
4 Too large a gap between piston and cylinder
5 Low tension of oil ring
6 Excessive wear of big-end bearing
7 Main oil seal cracked or damaged
8 Intake valve guide wrongly fitted
9 Excessive wear of cylinder taper and out / round
10 Engine head gasket cracked and damaged
4.9 Possible reasons for excessive noise during operation :
1 Wear and improper adjustment of engine parts
2 Abnormal condition due to detonation and auto-ignition
3 Poor quality fuel
4 Loose connecting rod