Make:
Mercury Marine (Mariner brand)
Model:
Mariner 40 / 45 / 50 / 50 Bigfoot 4-stroke outboard
Model Variants:
40 hp, 45 hp, 50 hp, 50 hp Bigfoot S
Production Years:
N/A - not specified for this model
Engine Type:
4-stroke, water-cooled gasoline outboard
Propulsion:
Outboard motor
Gearcase:
Bigfoot designation indicates larger gearcase for increased torque and durability
Target Audience:
Recreational boaters, commercial users needing reliable mid-range outboards, and marine technicians
Brand Heritage:
Mercury Marine, a division of Brunswick Corporation, is a leading manufacturer of marine engines
Design:
4-stroke engine for fuel efficiency, smooth operation, and no oil mixing
Bigfoot Advantage:
Larger gearcase provides increased torque and durability, suitable for demanding applications
Durability:
Engineering quality ensures dependable operation when properly maintained
Engine Mechanical:
Cylinder head, valve train, timing chain, pistons, connecting rods, crankshaft, cylinder block
Lubrication System:
Oil pump, oil filter, oil pressure relief valve, oil passages
Cooling System:
Water pump, thermostat, cooling passages, tell-tale, thermoswitch
Fuel System:
Fuel pump, carburetor(s), fuel filter, fuel tank, fuel lines, primer bulb
Ignition System:
Spark plugs, ignition coils, stator, trigger, CDM modules, ignition switch
Charging System:
Alternator, rectifier/regulator, battery, charging circuit
Starting System:
Electric starter, starter solenoid, neutral safety switch, starter relay
Gear Housing:
Forward gear, reverse gear, clutch dog, propeller shaft, bearing carrier, seals
Mid-Section:
Driveshaft, water tube, exhaust tube, mounts, swivel bracket, tilt tube
Power Trim and Tilt:
Trim motor, pump, cylinders, valves, relays, switches
Tiller/Remote Controls:
Throttle and shift cables, control handle, ignition switch, lanyard stop switch
Electrical System:
Wiring harness, fuses, relays, gauges, trim sender, warning systems
Maintenance:
Scheduled maintenance charts, fluid changes, filter replacements, spark plug service, impeller replacement
Troubleshooting:
Diagnostic flow charts, symptom-based guides for electrical, fuel, cooling, and mechanical issues
Repair:
Step-by-step disassembly, inspection, and reassembly with torque specifications
Adjustments:
Valve clearance, idle speed, throttle cable, shift cable, trim sender adjustment
Specifications:
Complete torque values, clearances, fluid capacities, and service limits
Diagrams:
Exploded views, wiring diagrams, and flow charts for accurate repair
Warnings:
Cautions and warnings for safe operation and repair
Parts Identification:
Part numbers and diagrams for ordering replacement components
Special Tools:
List of required special tools and their applications
File Format:
PDF (searchable, bookmarked, zoomable)
Compatibility:
Windows, macOS, Linux, iOS, and Android — any device with a PDF reader
Requirements:
A PDF reader application (e.g. Adobe Acrobat Reader, free)
Searchability:
Fully text searchable for fast lookup of any topic
Print Quality:
High-resolution digital pages, printable at full clarity
Binding Type:
N/A — digital download, no physical binding
Paper Type:
N/A — digital download, no physical paper
Engine Type:
4-stroke, water-cooled, gasoline
Displacement:
N/A - not specified for this model
Horsepower Range:
40 hp, 45 hp, 50 hp
Cylinders:
N/A - not specified for this model
Full Throttle RPM Range:
N/A - not specified for this model
Idle RPM:
N/A - not specified for this model
Fuel System Type:
Carbureted (typical for this era)
Fuel Requirements:
Unleaded gasoline, minimum 87 octane
Fuel Tank:
N/A - not specified for this model
Crash Test Ratings:
N/A - not applicable to outboard motors
Emergency Stop Switch:
Lanyard stop switch to shut off engine if operator leaves helm
Overheat Warning:
Audio/visual warning system
Low Oil Pressure Warning:
Audio/visual warning system
Neutral Start Protection:
Prevents starting in gear
Over-Rev Limiter:
Protects engine from excessive RPM
Break-In Service:
After first 20 hours, change gearcase lubricant and engine oil, check for leaks
Regular Service:
Every 100 hours or annually: change engine oil and filter, gearcase lubricant, spark plugs, fuel filter; inspect impeller
Winterization:
Stabilize fuel, fog cylinders, change lubricants, store properly
Engine Oil:
Mercury 4-Stroke Outboard Oil or equivalent NMMA FC-W certified
Gearcase Lubricant:
Mercury Premium Gear Lubricant or equivalent
Fuel:
Unleaded gasoline, minimum 87 octane, with 10% ethanol maximum
Known Issues and Wear Items
Common Wear Items:
Water pump impeller, spark plugs, fuel filter, anodes, propeller
Known Issues:
N/A - not specified for this model
