879841A03 Mercury COVER

Structure And Operation
Air Cleaner
* The air cleaner is a single element type.* The air cleaner is provided with a vacuator valve.* When the engine speed drops below a specified level, the vacuator valve is shaken by a consequent change in internal vacuum to automatically force out accumulated water and dust.Turbocharger
Waste Gate Mechanism
* The waste gate mechanism allows excess exhaust gas to escape from the turbocharger by means of an actuator in order to maintain the boost pressure at an appropriate level. This prevents overrunning of the turbocharger and excessive pressure buildups in the intake manifold.* The boost pressure is led via a rubber hose from the compressor cover to chamber A in the actuator. When the boost pressure in chamber A is less than the predetermined value, the actuator does not function and the waste gate valve remains closed. All exhaust gas then flows toward the turbine wheel. * When the boost pressure in chamber A exceeds the predetermined value, the waste gate valve opens, reducing the amount of exhaust gas flowing toward the turbine wheel. As a result, the speed of the compressor wheel, and thus the boost pressure, are reduced.Operating of Over-Boost Valve
* Over-boost valve operates when the boost pressure increases abnormally because of faulty operation of the waste gate mechanism.* If boost pressure of over-boost valve increases to become higher than the present value, the excessive boost pressure is discharged into the atmosphere, protecting the engine from excessive boost pressure. When the valve is operating, a pipe-blowing sound is generated. Troubleshooting
General Inspection And Adjustment
Cleaning And Inspection Of Air Cleaner Element
[Cleaning] * Blow a jet of compressed air at a pressure not higher than 685 kPa {7 kgf/cm2} against the inside surfaces of the element.* Move the compressed air jet up and down along all pleats of the filter paper element.
* For the frequency and timing of cleaning, refer to the relevant instruction manual. More frequent cleaning than necessary could damage the element or cause dust and foreign matter to be sucked into the engine.* Do not strike the element or hit it against another object to remove dust.* Do not blow compressed air against outside surfaces of the element. [Inspection] * Shine some electric light inside the element.* Replace the element if thin spots or broken parts are evident in the filter paper, or if the packing at the top of the element is damaged. Also replace the element if the dust on the element is damp with oily smoke or soot, regardless of the replacement schedule.Inspection Of Intake Manifold For Looseness
* Check the intake manifold and air inlet pipe mounting bolts and nuts for looseness. If any loose bolt or nut is found, tighten it to the specified torque. (See INTAKE MANIFOLD.)Inspection Of Exhaust Manifold For Cracks And Gas Leaks
* Visually check the external appearance of the exhaust manifold for cracks and traces of gas leak. If such damage is found, replace the exhaust manifold. (See EXHAUST MANIFOLD.)* Check the exhaust manifold mounting nuts for looseness. If any loose nut is found, tighten it to the specified torque. (See EXHAUST MANIFOLD.)Inspection Of Turbocharger For Cracks And Gas Leaks
* Visually check the external appearance of the turbocharger for cracks and traces of gas leak. If such damage is found, replace the turbocharger. (See TURBOCHARGER.)* Check the turbocharger mounting bolts and nuts for looseness. If any loose bolt or nut is found, tighten it to the specified torque. (See TURBOCHARGER.)Looseness Of Turbocharger
* Loosen the clamp which secures the air hose to the turbocharger and disconnect the air hose. * Turn the end of the compressor wheel shaft by hand. Confirm that the compressor wheel turns smoothly without contacting the compressor cover.* If any abnormality is found, disassemble and inspect the turbocharger. (See TURBOCHARGER.)Air Cleaner
Removal Sequence1 Dust indicator2 Vacuator valve3 Cover4 Element5 O-ring6 CaseX: Non-reusable parts Installation SequenceFollow the removal sequence in reverse.Service standards Tightening torque (Unit: N m {kgf m} Cleaning Procedure Cleaning: Outer Element* Blow a jet of compressed air at a pressure not higher than 685 kPa {7 kgf/cm2} against the inside surfaces of the element.* Move the compressed air jet up and down along all pleats of the filter paper element.
* For the frequency and timing of cleaning, refer to the relevant instruction manual. More frequent cleaning than necessary could damage the element or cause dust and foreign matter to be sucked into the engine.* Do not strike the element or hit it against another object to remove dust.* Do not blow compressed air against outside surfaces of the element.
Inspection Procedure Inspection: Outer Element* Shine some electric light inside the element.* Replace the element if thin spots or broken parts are evident in the filter paper, or if the packing at the top of the element is damaged. Also replace the element if the dust on the element is damp with oily smoke or soot, regardless of the replacement schedule. Inspection: Operation of dust indicator under specific negative pressure * Perform the following inspection and, if faulty, replace the dust indicator.* With no vacuum applied to the dust indicator, take measurement between the terminals 1 and 2. There should be no continuity.* Gradually apply vacuum to the dust indicator. Measure the vacuum when the continuity is made between the terminals 1 and 2.Turbocharger
Removal Sequence1 Turbocharger coupler2 Gasket3 Turbocharger insulator B4 Turbocharger insulator A5 Oil return pipe6 Gasket7 Eyebolt8 Oil pipe9 Turbocharger (See later sections.)10 Gasket*a: Exhaust manifoldX: Non-reusable parts Installation SequenceFollow the removal sequence in reverse.Tightening torque (Unit: N m {kgf m} Lubricant and/or sealant