Draining the Seawater System3A-22 Section 3A - Engine Air ...calabriaboats.com/merc_service_manual/90-863758070_3A.pdf · Manual Single‑Point Drain System (Alpha) ... 3A-33 Draining

Engine

90-863758070 APRIL 2008 Page 3A-1

3A

EngineSection 3A - Engine

Table of Contents

General Information.........................................3A-2Engine Rotation........................................3A-2Engine Lifting Provisions..........................3A-3Engine Oil Dipstick Relocation..................3A-3

Engine Compartment Construction..................3A-4Engine Compartment Ventilation..............3A-4Engine Compartment Seams....................3A-4Clearance.................................................3A-4Engine Bed Requirements........................3A-4Serviceability.............................................3A-5Engine Alignment....................................3A-19

Draining the Seawater System......................3A-22Drain System Identification.....................3A-22

Air Actuated Single Point Drain System................................................................3A-24Manual Single‑Point Drain System (Alpha)................................................................3A-28Three‑Point Manual Drain System..........3A-30Draining the Sterndrive...........................3A-32

Draining the Seawater System (Scorpion Models).......................................................................3A-33

Draining the Seawater System...............3A-33Drain System Identification.....................3A-33Air Actuated Single Point Drain System................................................................3A-35Multi‑Point Drain (MPD) System.............3A-38

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Page 3A-2 90-863758070 APRIL 2008

Lubricant, Sealant, AdhesivesTube Ref No. Description Where Used Part No.

9 Loctite 567 PST Pipe Sealant Fuel inlet fitting 92-809822

Special Tools

Alignment hook 91‑863375A 1

9190

Assists during engine alignment.

General InformationEngine Rotation

Engine rotation is described when observed from the rear of the engine (transmission end)looking forward (water pump end). All Mercury MerCruiser engines are left hand (LH)rotation. Propeller rotation is not necessarily the same as engine rotation; See Section 2—Transmission and Drive Line.

12710

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Engine Lifting ProvisionsEngines are equipped with a lifting eye at the front and the rear. Use a suitable sling withthe proper weight rating when lifting the engine.

ab b

33415

Typical enginea - Center lifting eye (engine alignment only)b - Lifting eye

NOTE: 8.1 H.O. and Horizon 8.1 engines require alignment hook (91‑863375‑1).

Alignment hook 91‑863375A 1

Engine Oil Dipstick RelocationSome models are equipped with an oil dipstick in the port and starboard dipstick tubes. Ifonly one dipstick is present and the engine is equipped with two dipstick tubes, you mayrelocate the oil dipstick.

ba

9366

Model shown is equipped with two oil dipsticksa - Dipstick option 1 b - Dipstick option 2

1. To relocate the oil dipstick:a. Remove the rubber cap from the dipstick tube.b. Remove the oil dipstick and insert it into the opposite dipstick tube.c. Place the rubber cap over the dipstick tube that is not being used.

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Page 3A-4 90-863758070 APRIL 2008

Engine Compartment Construction! WARNING

Improper boat design and construction may result in serious injury or death. Adhere toall applicable marine regulations (United States Coast Guard [USCG], European Union–Recreational Craft Directive [EU‑RCD], etc.) and the standards they reference (AmericanBoat and Yacht Council [ABYC], Society of Automotive Engineers [SAE], InternationalStandards Organization [ISO], etc.) when designing and constructing the boat and othercomponents, such as the engine compartment, fuel delivery system, or exhaust system.

Engine Compartment VentilationSee Section 4—Air Intake System.

Engine Compartment SeamsNOTICE

Water that runs onto the air intake may enter the engine and cause serious internal enginedamage. Design engine compartments so water cannot run onto the air intake or flamearrestor.

Exercise care in the design and construction of the engine compartment. Seams must belocated so that rain water is directed away from the air intake system and electrical system.

ClearanceIMPORTANT: The engine compartment must provide a minimum of 13 mm (½ in.)clearance between the boat and any component on the engine (i.e. exhaust manifold,elbow, oil pan, transmission case, etc.). This allows for engine mount deflection duringoperation.

Engine Bed RequirementsThe engine bed (i.e. stringers) must be designed to support the G‑forces imposed by theengine during the most severe duty. The bed must also handle the torque produced by theengine and the thrust generated by the propeller. Deflection of the engine bed could stressthe engine components, causing possible engine misalignment and transmission failure.The proper design of the engine bed varies considerably from one boat design to the next.Therefore, Mercury MerCruiser makes no attempt to provide detailed engine bed designrequirements to cover all possible applications. The proper design of the engine bed is leftto the boat manufacturer. The following general guidelines are provided:• The engine bed must be firmly affixed to the boat and should be made as large as

possible to distribute the load evenly. Reinforcements should be used wherenecessary. Mount pad locations should be as large as possible.

• The engine mounts are designed for the industry standard 572 mm (22½ in.) stringerwidths (center to center), but can accommodate widths up to 610 mm (24 in.).

• The engine bed must position the engine so that a minimum 6 mm (¼ in.) of up anddown adjustment exists on all four mounts after performing the final engine alignment.This is necessary to allow for realignment in the future. Engine mount isolators willcompress slightly over time.

• The front and rear mount locations on the engine bed should be in parallel planes. Thiscan be checked by tying a string from the left front mount location to the right rear mountlocation and another string from the right front to the left rear. The strings should justtouch were they cross.

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• The engine mounts must rest squarely on the engine bed so that the rubber isolator isnot preloaded in one direction or the other. Preloading the engine mount will causeincreased vibration.

1492114922

Typical front mount Typical rear mount• The metal ring must not contact the mount base on the front mount.

a

b

15889

Typical front mounta - Metal ring b - Mount base

• Engine mounts have provisions for 10 mm (3/8 in.) fasteners for securing mounts tothe engine bed. Fasteners should be selected as appropriate for the type of engine bedmaterial being used. The slot in front engine mounts should face forward. Do not installfasteners at an angle.

ServiceabilityAll engines require maintenance, and some require service repair within the life of theproduct. Consider serviceability when designing the engine compartment.In addition to customer and dealer satisfaction, consider the implications of serviceabilitywith respect to our warranty policy. The Mercury MerCruiser warranty policy states, in part,that reasonable access must be provided to the product for warranty service. Refer to thewarranty policy in the appropriate Operation, Maintenance, and Warranty Manuals. It statesthat removal or replacement of the boat partitions or material because of boat design fornecessary access to the product is not covered. Consider serviceability when designingthe boat and engine compartment to avoid these types of issues.Consider all engines options used in a boat when designing the engine compartment. Theengine size differences between some of the models as well as differences in service pointlocations may have a major effect on serviceability.

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Page 3A-6 90-863758070 APRIL 2008

The following is a list of the major service points to consider when designing the enginecompartment. Typical illustrations are shown to assist you in identifying these locations.These are typical views and may not accurately represent the model that you are workingwith. The specific engines, along with their installation drawings and the appropriateOperation, Maintenance, and Warranty Manual, should be used when doing the actualdesign work.

MAJOR SERVICE POINTS LIST

• Oil filter• Engine oil dipstick• Crankcase oil fill cap• Water separating fuel filter• Transmission fluid dipstick• Transmission/propeller shaft

coupler• Engine mounts• Ignition components• Electrical components bracket• Flame arrestor• Starter• Circulating pump• Alternator• Exhaust manifolds/elbows• Oxygen sensors (if equipped)• Exhaust catalysts (if equipped)• Ait intake system

• Thermostat housing• Shift and throttle linkages• Seawater pump• Drive belt• Water drains• Flush connector (if equipped)• Heat exchanger pressure cap and end caps (if equipped)• Closed cooling recovery bottle (if equipped)• Sea strainer (if equipped)• Battery• Transmission• Fuel system• Fuel coolers (if equipped)• Oil coolers• Cylinder heads• Complete engine removal

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ENGINE VIEW FOR PRODUCTS WITHOUT EMISSIONS CONTROL

c

a

h

de

g

i

j

k

b

b

f

24889

Typical 8.1 H.O. or Horizon 8.1 inboard side viewa - Transmission output flangeb - Engine mounts (4)c - Transmission dipstickd - Starter (inboard style)e - Transmission fluid coolerf - Ignition components

g - Dipstickh - Engine coveri - Exhaust manifold and elbow (2)j - Gen III Cool Fuel Module (Inboard

models)k - Seawater pump

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Page 3A-8 90-863758070 APRIL 2008

a

b

cd

ef

gh

i

14926

Typical 8.1 H.O. or Horizon 8.1 inboard front viewa - Drive beltb - Heat exchangerc - Coolant reservoird - Pressure cape - Flame arrestor

f - Electrical bracketg - Thermostat housingh - Alternatori - Circulating pump

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90-863758070 APRIL 2008 Page 3A-9

ENGINE VIEW FOR PRODUCTS WITH EMISSIONS CONTROL

34669

a

b

c

d

e

f

g

b

h

j

k

i

l

f

h

Typical 8.1 H.O. or Horizon 8.1 inboard side view with emissions controla - Transmission output flangeb - Engine mounts (4)c - Transmission dipstickd - Starter (inboard style)e - Transmission fluid coolerf - Ignition components

g - Dipstickh - Exhaust manifold and elbowi - Engine coverj - Gen III Cool Fuel Module (inboard

models)k - Seawater pumpl - Oxygen sensor cover plate

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Page 3A-10 90-863758070 APRIL 2008

a

b

c

d e f

g

h

i

34666

Typical 8.1 H.O. or Horizon 8.1 inboard front view with emissions controla - Drive beltb - Heat exchangerc - Coolant reservoird - Pressure cape - Flame arrestor

f - Electrical bracketg - Thermostat housingh - Alternatori - Circulating pump

OIL FILTERS

14333

a

Typical tow sports engine oil filtera - Engine‑mounted oil filter

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90-863758070 APRIL 2008 Page 3A-11

ab

14928

Typical inboard engine oil filtera - Engine oil fill capb - Remote oil filter

FUEL CONNECTIONSIMPORTANT: Be sure to remove the brass plug in the fuel inlet fitting.

14851

a

a

Models with boost pump Models without boost pumpa - Fuel inlet fitting

a

8269

Gen III Cool Fuel Module (Inboard models)a - Fuel inlet fitting

Tube Ref No. Description Where Used Part No.

9 Loctite 567 PST Pipe Sealant Fuel inlet fitting 92-809822

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Page 3A-12 90-863758070 APRIL 2008

ELECTRICAL

14957

Typical electrical components bracket

THROTTLE

a

bc

7926

Typical throttle cable and linkagesa - Flat washer and locknutb - Cable barrelc - Flat washer and locknut

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90-863758070 APRIL 2008 Page 3A-13

11527

a

b

c

Typical quick connect throttle cablea - Jam nutb - Cable barrelc - Throttle body bracket

SHIFT

a

cb

11531

Typical quick connect shift cablea - Jam nutb - Cable barrelc - Bracket

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Page 3A-14 90-863758070 APRIL 2008

a

7670

Typical transmissiona - Shift cable

7657

a

c

b

d

f

ge

Typical dual station transmissiona - Cable end guideb - Cable barrelc - Cable barrel studd - Elastic stop nut and washer

e - Spacerf - Cable end guide studg - Elastic stop nut and washer

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90-863758070 APRIL 2008 Page 3A-15

NOTE: Shift cables are not used on DTS transmissions

20418

ZF Marine (Hurth) transmission with electric shift— DTS models

FLUSH

a

6090

Typical flush connectora - Flush connector

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Page 3A-16 90-863758070 APRIL 2008

COOLANT

a

b

cd

8295

Typical heat exchanger for models with closed coolinga - Heat exchangerb - Gasket

c - Fastenerd - End cap

b

d

b

a

c

7804

Coolant recovery bottle modles with closed cooling engines except 8.1 H.O. and Horizon 8.1)a - Coolant recovery bottleb - Mounting holes

c - Hosed - Hose clamp

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90-863758070 APRIL 2008 Page 3A-17

SEA STRAINER

7533

STARTER

c

ba

7766

a - Rubber bootb - Starter solenoidc - 90‑amp fuse

THERMOSTAT

a

8219

a - Housing

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Page 3A-18 90-863758070 APRIL 2008

FUEL AND AIR INDUCTION

14339

FUEL SYSTEMS

ab

14931

a - Water‑separating fuel filter cover (MPI tow sports models only)b - Water‑separating fuel filter

a14340

Gen II fuel modulea - Fuel cooler

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90-863758070 APRIL 2008 Page 3A-19

d

a

b

c

e

f

g

h

8837

Gen III Cool Fuel modulea - Cool Fuel Moduleb - Cool Fuel Module harnessc - Filter capd - Filter assembly retaining screw

e - Fuel filter elementf - Filter cupg - Cool Fuel Module filter reservoirh - Filter cup seal

CYLINDER HEADS

6338

12728

Engine AlignmentProper alignment between the transmission, and the propeller shaft is essential to minimizenoise, vibration, and power loss and to avoid overstressing the transmission and drive linecomponents. Perform a preliminary alignment at engine installation. The final alignmentmust be done after the boat is in the water to compensate for any deflection in the hull. Onapplications with a rigid propeller shaft coupler, dsconnect the coupler from thetransmission for shipment. Check the alignment with the boat in the water. The requirementfor checking the alignment should be clearly communicated to your dealers, along with anunderstanding as to who is financially responsible.

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Page 3A-20 90-863758070 APRIL 2008

The complete alignment procedure is outlined in the installation manuals. Importantelements of this process include:• Align the engine to position the pilot on the propeller shaft coupler into the recess in

the transmission output flange so that the mating surfaces of the flange and the couplerare parallel within 0.07 mm (0.003 in.).

7534

• Check alignment by holding the flange and the coupler together and checking at 90°intervals with a feeler gauge. The coupler should be rotated 180° and alignmentrechecked to ensure that the coupler and flange are in alignment.

a

cb 7535

a - Propeller shaft couplerb - Feeler gaugec - Transmission output flange

Specification mm in.Transmission output flange to propeller shaft coupler alignmenttolerance 0.0–0.07 0.0–0.003

• The slot on the front mounts should face forward.• The adjusting nuts on the port and starboard mounts should be adjusted evenly.

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90-863758070 APRIL 2008 Page 3A-21

• A minimum of 6 mm (.25 in.) of up and down adjustment must exist on all four enginemounts after final alignment to allow for realignment in the future.

a

d

b

c

7536

a - 6 mm (.25 in.) minimumadjustment required for futurealignment

b - Adjusting nut

c - Locknutd - Slot

• Trunnions must not extend more than 45 mm (1.75 in.) and no less than 10 mm(.375 in.).

a

bc

d

7537

a - Trunnion extension 45 mm(1.75 in.). 10 mm (.375 in.) isnominal

b - Trunnion clamping screws andnuts

c - Locknutd - Tab washer

• Tighten mount locknuts securely. Bend the tab washer tab (that is closest to theadjacent flat on the locknut) against the flat to prevent it from loosening.

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Page 3A-22 90-863758070 APRIL 2008

• Tighten the trunnion clamping screws and nuts to specification.

a

b

c

7538

a - Coupler bolts and nuts (4)b - Set screwsc - Safety wire

• Tighten coupling bolts to specification. Secure set screws, if equipped, with safety wire

Description Nm lb. in. lb. ft.

Locknuts 68 — 50Coupler bolts 68 — 50

Draining the Seawater System! CAUTION

Water can enter the bilge when the drain system is open, damaging the engine or causingthe boat to sink. Remove the boat from the water or close the seacock, disconnect andplug the seawater inlet hose, and ensure the bilge pump is operational before draining.Do not operate the engine with the drain system open.

IMPORTANT: Only drain the seawater section of the closed‑cooling system.IMPORTANT: The boat must be as level as possible to ensure complete draining of thecooling system.Your power package is equipped with a drain system. Refer to Drain SystemIdentification to determine which instructions apply to your power package.IMPORTANT: The engine must not be operating at any point during the draining procedure.IMPORTANT: Mercury MerCruiser requires that propylene glycol antifreeze, mixed to themanufacturer's instructions, be used in the seawater section of the cooling system forfreezing temperatures or extended storage. Make sure that the propylene glycol antifreezecontains a rust inhibitor and is recommended for use in marine engines. Be certain to followthe propylene glycol manufacturer's recommendations.

Drain System IdentificationNOTE: All drain plugs are fitted with blue wing nuts.

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90-863758070 APRIL 2008 Page 3A-23

AIR ACTUATED SINGLE POINT DRAIN SYSTEM

33144

a

b c

da

d

c

33150

Closed‑cooled models Seawater-cooled modelsa - Blue drain plug locationb - Blue air pump

c - Air manifoldd - Green indicators

MANUAL SINGLE POINT DRAIN SYSTEM (ALPHA)

b

a

b

6128

a - Blue handle b - Blue drain plug location

THREE POINT MANUAL DRAIN SYSTEM

a a6126

a - Blue drain plug

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Page 3A-24 90-863758070 APRIL 2008

MULTI-POINT DRAIN (MPD) SYSTEM

10226 M110050

93235672

b

aa

b

6129

a - Side of cylinder block b - Bottom of exhaust manifolds

33155

Fuel cooler to thermostat housing

a

6131

a - Check valve (if equipped)

Air Actuated Single Point Drain SystemBOAT IN THE WATER

NOTE: This procedure is written for the air pump that is attached to the engine. However,any air source can be used.1. Close the seacock (if equipped) or remove and plug the water inlet hose.2. Remove the air pump from the engine.3. Ensure that the lever on top of the pump is flush with the handle (horizontal).4. Install the air pump on the actuator fitting.

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90-863758070 APRIL 2008 Page 3A-25

5. Pull lever on air pump (vertical) to lock pump on the fitting.

8293b

d

e

a

c

a - Actuator fittingb - Green indicatorsc - Manual release valve

d - Blue air pumpe - Lever (locking)

6. Pump air into the system until both green indicators extend and water drains from bothsides of the engine. The port side will begin draining before the starboard side.

7. Immediately remove the blue drain plug from the side of the thermostat housing or theheat exchanger. This must be removed within 30 seconds to properly vent the coolingsystem.

33144

a

b c

da

d

c

33150

Closed Cooled Models Seawater Cooled Modelsa - Blue drain plug locationb - Blue air pump


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Page 3A-26 90-863758070 APRIL 2008

8. Verify that water is draining from each opening. If not, use the Three Point ManualDrain System instructions.

a

b 6133

a - Port side drain location b - Starboard side drain location

9. Allow the system to drain for a minimum of five minutes. Pump air as necessary to keepthe green indicators extended.

10. Crank the engine over slightly with the starter motor to purge any water trapped in theseawater pump. Do not allow engine to start.

11. Reinstall the blue drain plug in the thermostat housing or heat exchanger.12. Remove the air pump from the air manifold and return it to the mounting bracket.13. Mercury MerCruiser recommends leaving the drain system open while transporting the

boat or while performing other maintenance. This helps ensure that all water is drained.14. Before launching the boat, pull up on the manual release valve. Verify that the green

indicators are no longer extended.

a6135

a - Green indicators

15. Open the seacock, if equipped, or unplug and reconnect the water inlet hose prior tooperating the engine.

BOAT OUT OF THE WATERNOTE: This procedure is written for the air pump that is attached to the engine. However,any air source can be used.1. Place the boat on a lever surface to ensure complete draining of system.2. Remove the air pump from the engine.3. Ensure that the lever on top of the pump is flush with the handle (horizontal).4. Install the air pump on the actuator fitting.

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90-863758070 APRIL 2008 Page 3A-27

5. Pull lever on air pump (vertical) to lock pump on the fitting.

8293b

d

e

a

c


d - Blue air pumpe - Lever (locking)


33144

a

b c

da

d

c

33150

Closed Cooled Models Seawater Cooled Modelsa - Blue drain plug locationb - Blue air pump


Engine

Page 3A-28 90-863758070 APRIL 2008


a

b 6133

a - Port side drain location b - Starboard side drain location


9. Crank the engine over slightly with starter motor to purge any water trapped in theseawater pump. Do not allow engine to start.

10. Remove the air pump from the air manifold and return it to the mounting bracket.11. Mercury MerCruiser recommends leaving the drain system open while transporting the



a6135


Manual Single‑Point Drain System (Alpha)BOAT IN THE WATER

1. Close the seacock (if equipped) or remove and plug the water inlet hose.2. Rotate the blue handle counterclockwise until it stops (approximately two turns). The

red on the handle shaft indicates that the drain system is open. Do not force the handleas this will create new threads.

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90-863758070 APRIL 2008 Page 3A-29

3. Immediately remove the blue drain plug from the side of the thermostat housing. Thismust be removed within 30 seconds to properly vent the cooling system.

a

b

6136

a - Blue handleb - Blue drain plug location

4. Visually verify that water is draining. If water does not drain, remove the blue drain plugfrom the distribution housing and drain manually.

a

b

33152

a - Blue drain plugb - Drain location ‑ orange or red

5. Allow the system to drain for a minimum of five minutes. We recommend leaving thedrain system open while transporting the boat or performing other maintenance.

6. Reinstall the blue drain plug in the thermostat housing.7. Close the drain system by rotating the blue handle clockwise until it stops and install

the blue drain plug, if removed. The handle is fully seated when no red is visible. Donot overtighten the handle, as this action will create new threads.

8. Open the seacock (if equipped) or unplug and reconnect the water inlet hose beforeoperating the engine.

BOAT OUT OF THE WATER1. Place the boat on a level surface to ensure complete draining of system.

Engine

Page 3A-30 90-863758070 APRIL 2008

2. Rotate the blue handle counterclockwise until it stops (approximately two turns). Thered on the handle shaft indicates that the drain system is open. Do not overtighten thehandle, as this action will create new threads.

a

6141

a - Blue handle

3. Visually verify that water is draining. If water does not drain, remove the blue drain plugfrom the distribution housing and drain manually.

a

b

33152

a - Blue drain plug b - Drain location ‑ orange or red

4. Allow the system to drain for a minimum of five minutes. We recommend leaving theplugs out while transporting the boat or performing other maintenance to ensure thatall water is drained.

5. Close the drain system by rotating the blue handle clockwise until it stops or installingthe blue drain plug. The handle is fully seated when no red is visible. Do not overtightenhandle, as this action will create new threads.

Three‑Point Manual Drain SystemBOAT IN THE WATER

NOTE: Use this procedure if your engine is not equipped with an air‑actuated single‑pointdrain system or if the air‑actuated single point drain system fails.1. Close the seacock (if equipped) or remove and plug the water inlet hose.

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90-863758070 APRIL 2008 Page 3A-31

2. Remove the blue drain plug from the distribution housing (lower front, port side).

6138

a

a - Blue drain plug

3. To properly vent the cooling system, remove the blue drain plug from the side of thethermostat housing within 30 seconds.

a

6139

a - Blue drain plug location

4. Remove the two blue drain plugs from the seawater pickup pump (front, starboard side).

a 6140

a - Blue drain plugs

5. Verify that water is draining from each opening.6. Allow the system to drain for a minimum of five minutes. We recommend leaving the

drain system open while transporting the boat or performing other maintenance toensure that all water is drained.

7. Crank the engine over slightly with starter motor to purge any water trapped in theseawater pickup pump. Do not allow the engine to start.

8. Before launching the boat or starting the engine, close the drain system by installingthe four blue drain plugs.


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Page 3A-32 90-863758070 APRIL 2008

BOAT OUT OF THE WATERNOTE: Use this procedure if your engine is not equipped with an air‑actuated single‑pointdrain system or if the single‑point drain system fails.1. Place the boat on a level surface to ensure complete draining of the system.2. Remove three blue drain plugs: one from the distribution housing (lower front, port side)

and two from the seawater pickup pump (front, starboard side).

aa6142

a - Blue drain plug

3. Verify that water is draining from each opening.4. Allow the system to drain for a minimum of five minutes. We recommend leaving the

drain system open while transporting the boat or performing other maintenance toensure that all water is drained.

5. Crank the engine over slightly with starter motor to purge any water trapped in theseawater pickup pump. Do not allow the engine to start.

6. Before launching the boat or starting the engine, close the drain system by installingthe three blue drain plugs.

Draining the SterndriveNOTE: This procedure is needed only for salty, brackish, mineral laden, or polluted waterapplications; and for freezing temperatures or extended storage.1. Insert a small wire repeatedly to make sure that vent holes, water drain holes, and

passages are unobstructed and open.

b

a

d

e

fc

6146

Sterndrive Water Drain Holesa - Speedometer pitot tubeb - Trim tab cavity vent holec - Trim tab cavity drain passage

d - Gear housing water drain hole (1each ‑ port and starboard)

e - Gear housing cavity vent holef - Gear housing cavity drain hole

Engine

90-863758070 APRIL 2008 Page 3A-33

NOTICEThe universal joint bellows may develop a set when stored in a raised or up position,causing the bellows to fail when returned to service and allowing water to enter the boat.Store the sterndrive in the full down position.

2. Lower the sterndrive unit to the full down/in position.3. For additional assurance against freezing and rust, after draining, fill the cooling system

with propylene glycol mixed to the manufacturer's recommendation to protect engineto the lowest temperature to which it will be exposed during freezing temperatures orextended storage

IMPORTANT: Mercury MerCruiser requires that propylene glycol antifreeze, mixed to themanufacturers instructions, be used in the seawater section of the cooling system forfreezing temperatures or extended storage. Make sure that the propylene glycol antifreezecontains a rust inhibitor and is recommended for use in marine engines. Be certain to followthe propylene glycol manufacturer's recommendations.

Draining the Seawater System (Scorpion Models)Draining the Seawater System

! CAUTIONWater can enter the bilge when the drain system is open, damaging the engine or causingthe boat to sink. Remove the boat from the water or close the seacock, disconnect andplug the seawater inlet hose, and ensure the bilge pump is operational before draining.Do not operate the engine with the drain system open.

IMPORTANT: Only drain the seawater section of the closed‑cooling system.IMPORTANT: The boat must be as level as possible to ensure complete draining of thecooling system.Your power package is equipped with a drain system. Refer to Drain SystemIdentification to determine which instructions apply to your power package.IMPORTANT: The engine must not be operating at any point during the draining procedure.IMPORTANT: Mercury MerCruiser requires that propylene glycol antifreeze, mixed to themanufacturer's instructions, be used in the seawater section of the cooling system forfreezing temperatures or extended storage. Make sure that the propylene glycol antifreezecontains a rust inhibitor and is recommended for use in marine engines. Be certain to followthe propylene glycol manufacturer's recommendations.

Drain System IdentificationNOTE: All drain plugs are fitted with blue wing nuts.

Engine

Page 3A-34 90-863758070 APRIL 2008

AIR ACTUATED SINGLE POINT DRAIN SYSTEM

a

b

33151

c

Scorpion modelsa - Air manifoldb - Green indicatorsc - Blue drain plug locations

MULTI-POINT DRAIN (MPD) SYSTEM

10226 M110050

93235672

b

aa

b

6129

a - Side of cylinder block b - Bottom of exhaust manifolds

a

6131

a - Check valve (if equipped)

Engine

90-863758070 APRIL 2008 Page 3A-35

Air Actuated Single Point Drain SystemBOAT IN THE WATER

NOTE: This procedure is written for the air pump that is attached to the engine. However,any air source can be used.1. Close the seacock (if equipped) or remove and plug the water inlet hose.2. Remove the air pump from the engine.3. Ensure that the lever on top of the pump is flush with the handle (horizontal).4. Install the air pump on the actuator fitting.5. Pull lever on air pump (vertical) to lock pump on the fitting.

8293b

d

e

a

c


d - Air pumpe - Lever (locking)



a

b

33151

c

a - Air manifoldb - Green indicatorsc - Blue drain plug locations

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Page 3A-36 90-863758070 APRIL 2008


a

b 6133

a - Port side drain locationb - Starboard side drain location


10. Crank the engine over slightly with the starter motor to purge any water trapped in theseawater pump. Do not allow engine to start.

11. Reinstall the blue drain plug in the thermostat housing or heat exchanger.12. Remove the air pump from the air manifold and return it to the mounting bracket.13. Mercury MerCruiser recommends leaving the drain system open while transporting the



a6135



BOAT OUT OF THE WATERNOTE: This procedure is written for the air pump that is attached to the engine. However,any air source can be used.1. Place the boat on a lever surface to ensure complete draining of system.2. Remove the air pump from the engine.3. Ensure that the lever on top of the pump is flush with the handle (horizontal).

Engine

90-863758070 APRIL 2008 Page 3A-37

4. Install the air pump on the actuator fitting.5. Pull lever on air pump (vertical) to lock pump on the fitting.

8293b

d

e

a

c


d - Air pumpe - Lever (locking)



a

b

33151

c

Scorpion modelsa - Air manifoldb - Green indicatorsc - Blue drain plug locations

Engine

Page 3A-38 90-863758070 APRIL 2008


a

b 6133

a - Port side drain locationb - Starboard side drain location


10. Crank the engine over slightly with starter motor to purge any water trapped in theseawater pump. Do not allow engine to start.

11. Remove the air pump from the air manifold and return it to the mounting bracket.12. Mercury MerCruiser recommends leaving the drain system open while transporting the



a6135


Multi‑Point Drain (MPD) SystemBOAT OUT OF THE WATER

1. Place the boat on a level surface to ensure complete draining of the system.2. Remove the blue drain plugs from the following locations. If necessary, clean out the

drain holes using a stiff piece of wire. Do so until the entire system is drained.a. Port and starboard side of cylinder block

Engine

90-863758070 APRIL 2008 Page 3A-39

b. Bottom of exhaust manifolds

10226 M110050

93235672

b

aa

b

6129

a - Cylinder block drain plugb - Exhaust manifold drain plug

c. Check valve

a

6131

a - Drain plug (if equipped)

3. On models with a seawater pickup pump, remove the two blue drain plugs. If theseawater pickup pump does not have blue drain plugs, or you are unable to accessthem, loosen the clamps and remove both hoses.

6145

b

a

a - Hose clampsb - Blue drain plugs

4. Crank the engine over slightly with the starter motor to purge any water trapped in theseawater pickup pump. Do not allow the engine to start.

5. After the cooling system has been drained completely, install the drain plugs, reconnectthe hoses, and tighten all hose clamps securely.

Engine

Page 3A-40 90-863758070 APRIL 2008

BOAT IN THE WATER1. Close the seacock (if equipped) or remove and plug the water inlet hose.2. Remove the blue drain plugs from the following locations. If necessary, clean out the

drain holes using a stiff piece of wire. Do so until the entire system is drained.a. Port and starboard side of cylinder blockb. Bottom of exhaust manifolds

10226 M110050

93235672

b

aa

b

6129

a - Cylinder block drain plug b - Exhaust manifold drain plug

c. Water‑circulating pump hose

a

6143

a - Drain plug

d. Check valve

a

6131

a - Drain plug (if equipped)

Engine

90-863758070 APRIL 2008 Page 3A-41

3. On models with a seawater pickup pump, remove the two blue drain plugs. If theseawater pickup pump does not have blue drain plugs, or you are unable to accessthem, loosen the clamps and remove both hoses.

6145

b

a

a - Hose clampsb - Blue drain plugs

4. Crank the engine over slightly with the starter motor to purge any water trapped in theseawater pickup pump. Do not allow the engine to start.

5. Before launching the boat or starting the engine, close the drain system by installingthe blue drain plugs.

6. Open the seacock, if equipped, or unplug and reconnect the water inlet hose beforeoperating the engine.

Engine

Notes:

Page 3A-42 90-863758070 APRIL 2008

Documents

Draining the Seawater System3A-22 Section 3A - Engine Air ...calabriaboats.com/merc_service_manual/90-863758070_3A.pdf · Manual Single‑Point Drain System (Alpha) ... 3A-33 Draining