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GASOLINE ENGINE 8.1 S INBOARD MODELS

Page 25 of 58

Engine Mount Pre-Adjustment

CAUTION

Engine compartment size may require the removal of additional components.

1. Remove engine cover.

2. Remove hardware holding engine to shipping pallet. Attach a suitable sling to lifting eyes

on engine. Lift engine from pallet with an overhead hoist.

76938

77516

a

b

a -

Rear Lifting Eye

b -

Front Lifting Eye

3. Remove L-shaped shipping bracket from both rear (transmission) mounts. Retorque

mount bracket attaching bolt to 47 lb-ft (64 Nm).

74623

a

b

Typical

a -

L-shaped Bracket

b -

Transmission Mount Bracket Attaching Bolt

IMPORTANT: Engine mounts must be adjusted, as explained in Steps 4. and 5., to
center mount adjustment and establish a uniform height on all mounts.

4. Check all 4 engine mounts (2 front, 2 rear) to ensure that distance from bottom of mount

to bottom of trunnion is as shown. If not, loosen mount locking nut and turn adjusting nut
in direction required to obtain proper dimension, then retighten locking nut.

Summary of Contents for MerCruiser 8.1S

Page 1: ...Rotation 6 Installation Requirements 9 Engine Bed 9 Engine Compartment 9 Exhaust System 12 Fuel Delivery System 16 Battery 18 EFI Electrical System Precautions 20 Instrumentation 20 Propeller Selecti...

Page 2: ...Mercury Marine or recommended tools from other suppliers It is the responsibility of the OEM to select the appropriate engine transom drive package including the correct gear ratio and propeller for a...

Page 3: ...r Road P O Box 1939 Fond du Lac WI 54936 1939 Outside of U S A order through Distribution Center or Distributor Lubricants Sealants Adhesives Description Part Number 2 4 C Marine Lubricant with Teflon...

Page 4: ...ber decal in position shown 77643 a a Specification Serial Number Decal Engine Rotation Engine rotation is described when observed from the rear of the engine transmission end looking forward water pu...

Page 5: ...on case Transmission rotation is described when viewed from the rear of transmission 22556 a b Typical Transmission Shown a Transmission Identification Plate b Output Flange Rotation Decal ZF Hurth Tr...

Page 6: ...sure to use correct rotation propeller and shift cable hook up for direction desired a b c b 71888 d e Velvet Drive 5000A 8 Down Angle Transmission a b f 74604 b g d Velvet Drive 5000V V Drive Transmi...

Page 7: ...Engine Transmission Input Shaft Rotation Direction LH c Transmission Output Propeller Shaft Rotation Direction LH d Direction Of Shift Lever Engagement Away From Flywheel e Transmission Output Propell...

Page 8: ...stallation drawings for each specific engine and transmission IMPORTANT Relative to horizontal never install the engine with the front pulley end down IMPORTANT On all engines a high angle of installa...

Page 9: ...ound Normally the quieter the engine compartment the more insulation material used resulting in less air space inside The less air space inside the engine compartment the hotter the inside air tempera...

Page 10: ...th a manometer TEMPERATURE Air temperatures inside the engine compartments have been measured in excess of 200 F 82 C The long term effect to fuel system components running at these excessive temperat...

Page 11: ...ra ture c A third thermocouple is needed if the fuel supply line between the tank and the fuel pump is higher than the fuel pump Place the third thermocouple at the highest point of the supply line to...

Page 12: ...and maximum load aboard Subtract b from a to find c If c is less than specified in chart select appropriate size exhaust elbow riser kit and exhaust extension kit if applicable that will correctly pos...

Page 13: ...tal Thereafter 3 of drop or 1 2 in 13 mm of drop per 12 in 305 mm relative to horizontal is a MINIMUM requirement for the rest of the exhaust system Exhaust hoses should not restrict the flow of disch...

Page 14: ...rndrives The 17 in 432 mm dimension can be re duced if necessary to a MINIMUM of 13 in 330 mm This dimension must be the same on both exhaust outlets e e e a a a a b b d d c c f f g g 75768 c a a e f...

Page 15: ...ow b Exhaust Hose Or Pipe c Muffler If Equipped d Waterline 71775 g f d b e a c Typical Waterlift Muffler Exhaust System a Vent Line 1 4 in 6 mm b Transom c Water Line d Exhaust Hose e Drain Valve f W...

Page 16: ...rom entering the tank It is recommended that the exact route and length of the fuel lines be established at the first installation of the engine to prevent problems later in connecting them to the eng...

Page 17: ...e been carefully designed to function properly together Do not install additional fuel filters and or water separating fuel filters between fuel tank and engine The installation of additional filters...

Page 18: ...o the engine that the alternator is mounted on When batteries for two different engines are connected one alternator will supply all of the charging current for both batteries Normally the other engin...

Page 19: ...in parallel to the cranking battery 5 The Model 32023A battery isolator is designed for this type of use 2 battery banks 2 charging sources 120 amps maximum alternator output 6 When the engines are r...

Page 20: ...s is used and a fused accessory panel is to be installed 40 amp current draw maximum be sure to connect it as shown in wiring diagram Do not connect accessory panel at any other location as wires in w...

Page 21: ...require that the propeller be changed to a lower pitch Warmer weather and greater humidity cause a loss of rpm Operating in a higher elevation causes a loss of rpm Operating with increased load additi...

Page 22: ...located as close to seawater pickup pump inlet as possible and in an area where an uninterrupted solid stream of water will flow past when boat is underway Water inlet hose connections must be made wi...

Page 23: ...e damage Engine coolant must flow continuously from the engine intake manifold to the engine water circulating pump NEVER close off or block the coolant flow to or from a heater All heater installatio...

Page 24: ...over the dipstick tube that is not being used 77629 a a b a a Dipstick Tube b Dipstick Battery Cable Connection IMPORTANT Engine electrical system is negative ground IMPORTANT Before connecting batter...

Page 25: ...L shaped shipping bracket from both rear transmission mounts Retorque mount bracket attaching bolt to 47 lb ft 64 Nm 74623 a b Typical a L shaped Bracket b Transmission Mount Bracket Attaching Bolt I...

Page 26: ...g in or out Mounts must be free to pivot when installing engine 70140 70158 e a e b f c d d c f b a Typical Front Mount Typical Rear Mount a Locking Nut b Adjusting Nut c Trunnion Clamp Bolts And Nuts...

Page 27: ...n at this time 72596 c a b a Propeller Shaft b Propeller Shaft Coupler c Transmission Output Flange IMPORTANT Engine bed must position engine so that a minimum of 1 4 in 6 mm up and down adjustment st...

Page 28: ...adjust engine position at this time IMPORTANT Engine bed must position engine so that a minimum of 1 4 in 6 mm up and down adjustment still exists on all 4 mounts after performing final alignment Thi...

Page 29: ...s with solid couplings as well as flexible couplings 1 Check mating surfaces on transmission output flange and propeller shaft coupler to make sure they are clean and flat 2 Follow instructions a or b...

Page 30: ...propeller shaft coupler should engage recess on transmission output flange face with no resistance 72597 Incorrect Correct NOTE Some propeller shaft couplers may not have a shoulder on mating face On...

Page 31: ...nment by hand holding coupling faces tightly together and checking for a gap between coupling faces with a 003 in 0 07 mm feeler gauge at 90 intervals 75534 c b a Velvet Drive 50608 50609 a c b c a b...

Page 32: ...Washers d Lag Bolt NOTE Some rear mounts have one 1 clamping bolt and nut on each side b TO MOVE ENGINE TO THE LEFT OR RIGHT Loosen clamping bolts and nuts on all 4 mount brackets move engine to the l...

Page 33: ...ing face plane of the couplers 10 Connect propeller shaft coupler to transmission output flange Attach couplers together with bolts lockwashers and nuts Torque to 50 lb ft 68 Nm NOTE If propeller shaf...

Page 34: ...to the upper fitting 77512 a a Seawater Inlet Hose Attached To Upper Fitting Fuel Supply Connection A flexible fuel line must be used to connect fuel line to engine to absorb deflection when engine i...

Page 35: ...alarm to wire bundle with sta strap provided 3 Connect PURPLE wire from alarm to any 12 volt source on switched side of ignition switch Tighten connection securely and coat with Quicksilver Liquid Ne...

Page 36: ...Coat both battery cable terminals with Quicksilver Liquid Neoprene After liquid neoprene has dried slide rubber boot over positive cable connection 74660 74503 b d a c a Negative BLK Battery Cable b...

Page 37: ...ts which could eventually result in burned through exhaust hoses Exhaust hoses and or tubes must be cor rectly connected to exhaust elbows so that they do not restrict the flow of discharge water from...

Page 38: ...er fitting on the starboard exhaust manifold front end on V drives rear end on conventional inboards IMPORTANT If not using a shaft log seal this fitting must remain plugged 2 Attach the shaft log sea...

Page 39: ...or Left Hand Propeller Shaft Rotation Shift cable hookup at remote control must result in shift cable end guide moving in direction A when remote control handle is placed in forward position For Right...

Page 40: ...control is in NEUTRAL position b Push in on control cable end with enough pressure to remove play mark position a on tube c Pull out on control cable end with enough effort to remove play mark positio...

Page 41: ...en Right Hand Propeller Shaft Rotation Is Desired d Poppet Ball Must Be Centered In This Detent Hole For Neutral Position e Install Shift Lever Stud In This Hole when Using Quicksilver Shift Cables 8...

Page 42: ...ver b Shift Cable Bracket 13 Install nut and washer to cable end guide stud Tighten until they contact then loosen 1 2 turn 14 Install nut and washer to cable barrel stud Tighten securely but DO NOT o...

Page 43: ...eopardized if the shift lever pop pet ball or spring is permanently removed if the shift lever is repositioned or changed in any manner or if remote control and cable do not position shift lever corre...

Page 44: ...re distance between marks a and b and mark position c half way between marks a and b 22024 a b c c 5 Center cable end play then adjust cable barrel to align holes in barrel and in cable end guide with...

Page 45: ...le travel and must be replaced 13 Reattach nut and washer to cable end guide stud Tighten until they contact then loosen 1 2 turn 14 Reattach nut and washer to cable barrel stud Tighten securely but D...

Page 46: ...Cable End Guide b Cable Barrel c Cable Barrel Stud d Elastic Stop Nut And Washer e Spacer f Cable End Guide Stud g Elastic Stop Nut And Washer NOTE For models equipped with a dual station shift bracke...

Page 47: ...uide moving in direction B when remote control handle is placed in forward position 23242 A B WARNING Avoid serious injury or property damage caused by improper shifting Anchor stud for shift cable mu...

Page 48: ...aching points on transmission 6 Temporarily install shift cable Do not secure at this time 73587 a Typical a Shift Cable End Guide IMPORTANT Transmission is fully in gear when shift lever comes to a s...

Page 49: ...12 If proper positioning is still not obtained remote control does not provide sufficient shift cable travel and must be replaced 73587 a b Typical ZF Hurth Transmission Shown a Shift Lever b Shift Ca...

Page 50: ...pacer Fits Over Bushings d Bushings e Cable Barrel Location f Spacer Fits Over Stud g Cable Barrel Stud h Cable End Guide Stud 73587 50229 g h e a f b d e c b Typical Single Cable Rear Entry a Cable E...

Page 51: ...es b Locknut And Washer c Spacer Fits Over Stud d Bushings e Cable Barrel Locations f Cable Barrel Stud g Cable End Guide Stud 73591 50073 e f g e b c d a b Typical Dual Cable Rear Entry a Cable End G...

Page 52: ...tested on land water must be supplied to seawater pickup pump DO NOT run engine above 1500 rpm Boat In The Water Tests IMPORTANT Engine alignment MUST BE CHECKED with boat in the water fuel tanks fil...

Page 53: ...ngine will be exposed to freezing temperatures ensure closed cooling section is filled with an ethylene glycol antifreeze and water solution properly mixed to pro tect engine to lowest temperature to...

Page 54: ...s extend and water drains from both sides of the engine 6 Most water will drain from the engine in 3 4 minutes however some will remain trapped in the heat exchanger In order to prevent freeze damage...

Page 55: ...front and rear of cool fuel cell and from the seawater pump 2 Remove end caps sealing washers and gaskets from heat exchangers 71515 a b c d a Heat Exchanger b Gaskets c Sealing Washer d End Cap 3 Cl...

Page 56: ...lant And Water Flow Diagrams NOTE Certain components in the following diagram may look different than on your particular power package but the water and coolant flow paths remain similar on all engine...

Page 57: ...ator 3 Transmission Cooler 4 Oil Cooler 5 Fuel Cooler 6 Air Actuator 7 Heat Exchanger 8 Thermostat 9 Crossover 10 Water Circulating Pump 11 Coolant Reservoir 12 Exhaust Manifold 13 Elbow 14 Water And...

Page 58: ...onnections tight Idle RPM within specifications Correct rotation propeller installed and torqued Throttle shift and steering system Forward Neutral Reverse fasteners tightened properly gear operation...

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