Tohatsu M4C Specifications
| Engine Model: Tohatsu M4C |
| Engine Type: 2-stroke 1-cylinder gasoline outboard engine |
| Total Displacement: 6.2 cu.in (102 cc) |
| Rated Engine Power: 4 Hp (2.9 kW) at 5500 rpm |
| Fuel System: Carburetor |
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The Tohatsu M4C is a technologically
uncomplicated yet highly effective outboard that distinguishes itself
through its lightweight and portable design, offering boaters an
incredible power-to-weight ratio. Its engineering focus is on
reliability and user convenience, highlighted by the loop-charged
induction system for smooth operation and fuel economy, and a CD
ignition system for quick and easy starts.
Users benefit from a simple tiller control with forward, neutral, and
reverse gears, along with a shallow water drive for navigating in low
waters. The engine is engineered for durability in marine environments,
incorporating high-grade marine aluminum alloy and zinc coating on
internal water passages for superior corrosion resistance, making it a
reliable and clean-operating powerplant for small boat applications.
Engine Model: Tohatsu M4C
Engine Type: 2-stroke, single-cylinder, gasoline outboard engine
Number of Cylinders: 1
Displacement: 6.2 cu in (102 cc)
Cylinder Bore: 2.17 in (55.0 mm)
Piston Stroke: 1.69 in (43.0 mm)
Maximum Engine Power: 4.0 hp (2.9 kW)
Maximum Engine Speed: 4500-5500 rpm
Lubrication System: Pre-mixed fuel and oil
Exhaust System: Through propeller hub
Cooling System: Water-cooled
Ignition System: Flywheel magneto CDI (Capacitor Discharge Ignition)
Starting System: Manual recoil starter
Cylinder Bore Inside Diameter: 2.165-2.166 in (55.00-55.01 mm)
Piston to Cylinder Clearance: 0.0012-0.0024 in (0.03-0.06 mm)
Top Ring End Gap: 0.008-0.016 in (0.20-0.40 mm)
Second Ring End Gap: 0.008-0.016 in (0.20-0.40 mm)
Top Ring Side Clearance: 0.0011-0.0028 in (0.03-0.07 mm)
Second Ring Side Clearance: 0.0008-0.0024 in (0.02-0.06 mm)
Piston to Piston Pin Clearance: 0.0002-0.0031 in (0.01-0.08 mm)
Connecting Rod Big End Side Clearance: 0.0051-0.0146 in (0.13-0.37 mm)
Fuel System Type: Carburetor
Fuel Type: Unleaded gasoline, 87 octane minimum
Fuel Consumption: 1.6 L/hr
Fuel Tank Capacity: 2.5 L (0.66 US gal) integral fuel tank
System Type: Pre-mix (fuel/oil ratio 50:1)
Engine Oil Type: Genuine two-stroke outboard oil, NMMA TCW-III certified
Engine Oil and Fuel Ratio: 50 parts unleaded gasoline to 1 part
two-stroke engine oil
System Type: Water cooling
Water Pump: Driven by driveshaft, with rubber impeller
| Mid Section and Lower Unit |
Mid Section: Integral driveshaft housing
Steering System (Std): Tiller handle
Steering System (Opt): Remote control
Shift System: Dog clutch
Gear Shift: Forward - Neutral - Reverse
Gear Ratio: 2.15:1 (13:28)
Gearcase Capacity: 0.20 qts (0.19 L)
Gear Lubricant Type: Genuine Tohatsu gear oil or API GL-5, SAE 80, SAE
90
Trim System: Manual Trim and Tilt
Trim Positions: 6 positions
Shallow Water Drive: Standard
Maximum Tilt Angle: 75 degrees
Propeller Types: 3-blade
Propeller Diameter Range: 7.8 in (198 mm) to 7.9 in (200 mm)
Propeller Pitch Range: 6 in (152 mm) to 9 in (229 mm)
Propeller Material: Aluminum
Overall Length: 27.6 in (700 mm)
Overall Width: 12.2 in (310 mm)
Overall Height (Short Shaft model): 39.6 in (1005 mm)
Overall Height (Long Shaft model): 44.6 in (1135 mm)
Transom Height (Short Shaft): 15 in (381 mm)
Transom Height (Long Shaft): 20 in (508 mm)
Outboard Weight (Short Shaft): 44.0 lbs (20.0 kg)
Outboard Weight (Long Shaft): 45.0 lbs (20.5 kg)
Engine Fuel: Unleaded gasoline, 87 octane minimum
Engine Oil: NMMA TCW-III certified two-stroke oil
Fuel/Oil Ratio: 50:1
Gear Lubricant: API GL-5, SAE 80 to 90
Gearcase Capacity: 0.20 qts (0.19 L)
Ignition Timing: 30 degrees BTDC
Spark Plug Type: NGK BP7HS-10 or NGK BPR7HS-10
Spark Plug Gap: 0.035-0.039 in (0.9-1.0 mm)
Every 50 Hours: Check spark plug,
check fuel line, clean fuel tank, check anodes, check gear oil level,
check propeller, check starter rope for wear.
Every 100 Hours: Check cooling
system operation, check water pump, check/adjust carburetor.
Every 200 Hours: Replace gear oil,
replace spark plug, replace water pump impeller.
Cylinder Head Bolt: 18.8 lb-ft (25.5 Nm)
Magneto Nut: 43.7 lb-ft (59 Nm)
Crankcase Bolt: 8.2 lb-ft (11 Nm)
Propeller Nut: 9.0 lb-ft (12 Nm)
Mounting Bolts: 13.0 lb-ft (30 Nm)
Gear Oil Plug: 3.0 lb-ft (4 Nm)
Spark Plug: 20.0 lb-ft (27 Nm)
The Tohatsu M4C is a versatile outboard ideally suited for a wide range
of small, portable watercraft. Its light weight and compact dimensions
make it an excellent choice for powering inflatable boats, dinghies, and
small tenders used as shore craft for larger vessels.
It is also a popular powerplant for small fishing boats, jon boats, and
canoes used on lakes and rivers, where its portability allows for easy
transport and storage. The engine's straightforward design and reliable
operation make it well-matched for recreational boaters, anglers, and as
an auxiliary motor for sailboats, where efficiency and ease of use are
paramount.
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