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Tohatsu MFS20C Specifications
| Engine Model: Tohatsu MFS20C |
| Engine Type: 4-stroke 2-cylinder SOHC gasoline outboard engine |
| Total Displacement: 21.4 cu.in (351 cc) |
| Rated Engine Power: 20 Hp (14.7 kW) at 6000 rpm |
| Fuel System: Fuel Injection |
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| General Technical Data |
The Tohatsu MFS20C is a two-cylinder,
four-stroke outboard delivering 20 horsepower. Available in several
configurations - including manual start with tiller (MF), electric start
with tiller (EF, EFT), and electric start with remote control (EP, EPT)
- this engine represents a modern, fuel-injected powerplant. It is
engineered for quiet operation, excellent fuel economy, and
environmental friendliness, making it a popular choice for boaters
seeking a clean and efficient alternative to two-stroke engines.
The design focuses on advanced four-stroke technology, offering features
like a trochoid oil pump for forced lubrication and a through-hub
exhaust for quieter running. The Tohatsu MFS20C is a well-engineered and
dependable four-stroke outboard. Its two-cylinder design provides smooth
operation with excellent fuel economy, a direct benefit of its
four-stroke cycle and advanced fuel injection system.
The engine is built with corrosion-resistant materials, enhancing its
longevity, especially in saltwater environments. An Electronic Safety
Governor (ESG) protects the engine from over-revving by limiting RPM
above approximately 6,400 r/min. The availability of power trim and tilt
on select models adds to its user-friendly nature, and features like an
oil pressure warning lamp and start-in-gear protection provide
additional operational security.
Engine Model: Tohatsu MFS20C MF, EF, EFT, EP, EPT.
Engine Type: 4-Stroke.
Number of Cylinders: 2.
Bore x Stroke: 61 mm x 60 mm (2.40 in x 2.36 in).
Piston Displacement: 351 cc (21.4 cu in).
Power Output: 14.7 kW (20 HP).
Full Throttle Operating Range: 5400-6100 r/min.
Idle Speed in Neutral Gear: 950 r/min.
Minimum Trolling Speed in Forward Gear: 900 r/min.
Fuel System: Fuel Injection.
Exhaust System: Through-hub exhaust.
Cooling System: Water cooling.
Lubrication System: Forced lubrication by trochoid pump (wet sump).
Starting System: Manual (MF model) / Electric starter motor (EF, EFT,
EP, EPT models).
Ignition System: Flywheel Magneto CDI (Capacitor Discharge Ignition).
Spark Plugs: NGK DCPR6E.
Steering (MF, EF, EFT): Tiller Handle.
Steering (EP, EPT): Remote Control.
Trim System (MF, EF, EP): Manual trim and tilt.
Trim System (EFT, EPT): Power trim and tilt.
Trim Position: 6.
Gear Shift: Dog clutch (F-N-R).
Gear Reduction Ratio: 2.15 (13:28).
Fuel: Unleaded Regular Gasoline with an anti-knock index (R+M/2) of 87
or higher, or a Research Octane Number (RON) of 91 or higher.
Fuel Tank Capacity: 12 L (3.2 US gal) Separate fuel tank.
Engine Oil: API SF, SG, SH, SJ, SL, SM SAE 10W-30.
Engine Oil Capacity: 1.0 L (1.05 qt).
Gear Oil: API GL-5, SAE 80-90.
Gear Oil Capacity: 0.37 L (0.39 qt).
| Powerhead |
The MFS20C features a single overhead camshaft (SOHC), two-cylinder powerhead. The four-stroke cycle - intake, compression, power, and exhaust - is completed in two crankshaft revolutions, contributing to its clean and efficient operation.
The engine utilizes a timing belt to drive the camshaft, which actuates the valves via rocker arms. Valve adjustment is critical and should be checked by a dealer. It is built with a high-grade marine aluminum alloy for the block and other components, providing excellent corrosion resistance and durability while keeping weight low.
| Fuel System |
The fuel system features electronic fuel injection, which precisely meters fuel for optimal combustion, resulting in improved fuel economy, easier starting, and reduced emissions compared to carbureted systems. It is designed to run on standard 87-octane unleaded gasoline.
A separate 12-liter fuel tank is provided with the outboard. The system includes a fuel filter that requires periodic inspection and cleaning.
| Lubrication System |
The lubrication system is a forced, wet-sump design utilizing a trochoid oil pump. The engine oil is contained in a sump within the engine and is circulated under pressure to lubricate internal components.
The oil level must be checked regularly using a dipstick and maintained between the upper and lower level marks. The recommended oil is a high-quality 4-stroke outboard oil, such as API class SF to SM, SAE 10W-30. The total oil capacity is 1.0 liter.
| Cooling System |
Cooling is managed by a forced water system that is thermostatically
controlled to maintain a consistent engine temperature for optimal
performance and longevity. The system features a water pump that must be
inspected and the impeller replaced periodically.
An overheat warning system alerts the operator if the engine approaches
a critical temperature. A cooling water check port on the front of the
drive shaft housing allows the operator to verify proper water flow
during operation.
| Mid Section and Lower Unit |
The MFS20C is fitted with a durable mid section and lower unit housing a
forward-neutral-reverse dog clutch. The gear reduction ratio is 2.15:1
(13:28). The recommended gear oil is an API GL-5, SAE 80-90 grade, with
a total capacity of 0.37 liters.
The lower unit is equipped with a replaceable trim tab, which also
serves as a sacrificial anode for corrosion protection. The through-hub
exhaust system contributes to quieter operation.
| Trim and Tilt System |
The MFS20C is offered with two types of trim systems. The MF, EF, and EP models feature a manual trim and tilt system with six trim positions. The EFT and EPT models are equipped with a power trim and tilt system, which uses an electric hydraulic pump to adjust the motor's angle. The power trim system has a manual relief valve for emergency operation.
| Propeller Information |
The recommended propeller selection range for the MFS20C is from 6 to 11.5 inches of pitch. The correct propeller must be selected so that the engine operates within its wide-open throttle (WOT) range of 5400-6100 r/min under a normal load for optimal performance and engine longevity.
The standard propeller is made of aluminum and has three blades. When installing or removing the propeller, a block of wood should be placed between the propeller blade and the anti-ventilation plate to hold it, and a new split pin must always be used.
| Dimensions and Weight |
Overall Length (MF, EF, EFT): 980 mm (38.6 in)
Overall Length (EP, EPT): 640 mm (25.2 in)
Overall Width (MF, EF, EFT): 365 mm (14.4 in)
Overall Width (EP, EPT): 345 mm (13.6 in)
Overall Height (Short Shaft): 1065 mm (41.9 in)
Overall Height (Long Shaft): 1215 mm (47.8 in)
Overall Height (Ultra Long Shaft): 1342 mm (52.8 in)
Transom Height (Short Shaft): 413 mm (16.3 in)
Transom Height (Long Shaft): 562 mm (22.1 in)
Transom Height (Ultra Long Shaft): 689 mm (27.1 in)
Weight (MF Short Shaft): 51.5 kg (114 lb)
Weight (EF Short Shaft): 55 kg (121 lb)
Weight (EFT Short Shaft): 62 kg (136 lb)
Weight (EP Short Shaft): 54 kg (119 lb)
Weight (EPT Short Shaft): 61 kg (134 lb)
Weight (MF Long Shaft): 53 kg (117 lb)
Weight (EF Long Shaft): 56.5 kg (125 lb)
Weight (EFT Long Shaft): 63.5 kg (139 lb)
Weight (EP Long Shaft): 55.5 kg (122 lb)
Weight (EPT Long Shaft): 62.5 kg (138 lb)
Weight (MF Ultra Long Shaft): 54.5 kg (120 lb)
Weight (EF Ultra Long Shaft): 58 kg (128 lb)
Weight (EFT Ultra Long Shaft): 65 kg (142 lb)
Weight (EP Ultra Long Shaft): 57 kg (126 lb)
| Maintenance Data |
First 20 Hours / 1 Month: Initial dealer inspection. Every 50 Hours / 3
Months: Check and clean the fuel filter. Inspect and clean spark plugs,
adjust gap to 0.8-0.9 mm (0.031-0.035 in). Check and re-tighten all
accessible bolts and nuts. Apply grease to all sliding and rotating
parts and grease nipples. Check engine oil level.
Every 100 Hours / 6 Months: Change engine oil. Change gear oil,
inspecting for water or metal particles. Have a dealer check valve
clearance and ignition timing. Inspect the water pump impeller for wear.
Annually / Every 100 Hours: Replace the water pump impeller regardless
of apparent condition. Replace spark plugs. Replace timing belt (by
dealer).
| Tightening Torques |
Cylinder Head Bolts: 19 Nm
Main Bearing Bolts: 24 Nm
Connecting Rod Bolts: 19 Nm
Propeller Nut: 15-20 Nm (11-14.8 lb-ft)
Spark Plugs: 18 Nm (13.3 lb-ft)
Engine Oil Drain Bolt: 20-25 Nm (Use new gasket)
Gear Oil Drain/Fill Screws: 4-6 Nm (Be careful not to over-tighten)
Mounting Bolts (Transom): 20-30 Nm (14.8-22.1 lb-ft)
| Boat Applications |
Fishing Boats: An excellent choice for small aluminum tiller-steered boats, jon boats, and lightweight center consoles. Utility Boats: Well-suited for skiffs, inflatables, and other light commercial or recreational utility craft used in sheltered waters. Auxiliary Power: Can serve as reliable auxiliary power for larger sailing yachts.
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