Target Audience:
Yamaha dealers, marine technicians, and DIY owners performing parts identification and ordering for the 4MHQ outboard
Advantage:
Factory-issued parts diagrams with Yamaha part numbers ensure exact-fit replacement components and correct assembly order
Illustrated Parts Breakdowns:
Exploded diagrams for each major assembly
Part Number Reference:
Official Yamaha part numbers for every component
Power Head:
Cylinder, crankcase, cylinder head, pistons, crankshaft assemblies
Fuel System:
Fuel tank, fuel pump, carburetor components
Ignition System:
Flywheel magneto, ignition coil, spark plug components
Cooling System:
Water pump, impeller, cooling passages
Lower Unit / Gear Case:
Gears, driveshaft, propeller shaft, propeller
Steering and Tiller Handle:
Tiller handle, throttle and shift linkages
Clamp Bracket and Swivel:
Transom brackets, steering swivel, trim hardware
Anodes and Fittings:
Zinc anodes, fasteners, brackets, decals
Parts Identification:
Exploded-view illustrations keyed to part tables
Parts Ordering Reference:
Official Yamaha part numbers and descriptions for ordering
Assembly Reference:
Component relationships shown for correct reassembly order
Depth:
Parts-catalog level: exploded diagrams and part tables; not a step-by-step repair manual
Illustrations:
Line-art exploded views for every assembly group
Torque Specifications:
N/A - not included in a parts manual; see the corresponding service manual
Wiring Diagrams:
N/A - not included; see the service manual for electrical schematics
Part Numbers:
Complete Yamaha factory part numbers for each component
Quantity Columns:
Required quantity per assembly listed
Supersession:
Current replacement part numbers as issued in the original catalog
Hardware Groupings:
Bolts, nuts, washers, and seals listed per assembly
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:
Single-cylinder 2-stroke outboard
Displacement:
Approximately 2 cylinders? No - single cylinder, 4 hp class
Starting System:
Manual recoil start
Performance:
N/A - horsepower rating of 4 hp per model designation; detailed dyno figures not published in parts manual
Fuel Delivery:
Carbureted
Fuel Tank:
Integral / remote portable tank per model configuration
Standard Transmission:
Forward - Neutral - Reverse gear selection via shift lever
Optional Transmission:
N/A - single gearcase configuration for this model
Gear Ratio:
N/A - not specified in a parts manual; see service manual
Propeller:
Aluminum propeller, model-specific part number listed in the manual
Wheelbase:
N/A - not applicable to an outboard motor
Transom Shaft Length:
N/A - not specified; verify with Yamaha model code (S/L suffix)
Length:
N/A - not specified in a parts manual
Curb Weight:
N/A - not listed in a parts manual; typically in the 20 kg range for 4 hp portables, verify with official specs
Crash Test Information:
N/A - not applicable to an outboard motor
Active / Passive Features
Emergency Stop:
Engine stop switch lanyard provision
Neutral Start Protection:
N/A - not specified for this model
Over-Rev Limiter:
N/A - not specified in a parts manual; verify with service manual
Routine Service:
N/A - intervals are covered in the service/owner's manuals, not the parts manual
Parts Replacement Reference:
Wear parts such as impeller, gaskets, spark plug, and propeller hardware are identified in the diagrams
Gear Oil:
N/A - specification listed in service manual; correct seals and fill/ drain plugs identified in parts manual
Fuel System Components:
Carburetor gaskets, fuel line, and filter parts listed for renewal
Water Pump Impeller:
Common service item; complete impeller kit parts listed
Carburetor Gaskets and Diaphragms:
Listed for periodic renewal
Anodes:
Zinc anode part numbers listed for corrosion protection
Manufacturer:
Yamaha Motor Co., Ltd., a leading Japanese marine engine manufacturer
Model Line:
The 4MH series belongs to Yamaha's portable 4 hp outboard family, widely used on small boats, tenders, and dinghies
Model Code:
4MHQ designates the specific variant within the 4 hp range
Production Location:
N/A - manufactured by Yamaha Motor Co., Ltd.; specific plant not stated in the parts manual
