Basic Parts and Operation: Four-Stroke Cycle Engine

The largest part of the engine is the:

• cylinder

• flywheel

• crankshaft

• cylinder assembly

The two smaller holes alongside the cylinder are:

• the main bearings

• camshaft bearings

• intake and exhaust ports

• none of these are correct

The crankshaft has:

• two main journals

• a crankpin

• a small gear

The piston is attached to the crankshaft by means of:

• the piston pin

• the compression rings

• the piston pin and the connecting rod

• the piston crown

The armature is used to fire the spark plug. The current is created by:

• the battery

• an ignition coil

• a moving magnet

• the flywheel

The governor for the engine is used to:

• set the idle speed

• maintain a required speed

• control the airflow through the fins

• move the air vane

"Four-stroke cycle engine" means that the:

• engine has no valves

• crank revolves four times

• piston moves up and down four times per cycle

• camshaft revolves at four times engine speed

During the exhaust stroke:

• the piston moves down

• the intake valve is open

• the crankshaft reciprocates

• none of these are correct

Answer explanation

The piston is moving up. Exhaust valve is open and the intake valve is closed. The crankshaft is rotating.

The lobe on the camshaft comes into direct contact with the:

• exhaust valve

• crankshaft

• tappet

• camshaft bearings

The ignition timing is correct when the engine:

• is set to 5 degrees before top dead center

• is assembled

• fuel air misture is 15 to 1

• none of these are correct

Answer explanation

The ignition timing is correct when the spark fires just an instant before the piston reaches top dead center.