50 HP 4-Stroke Midrange Outboard

Model MFS50

What is the one thing every boater looks for in an outboard motor? The lightest weight motor possible. Tohatsu's all new 50hp four stroke has what you need at just 209 pounds, the lightest weight motor in its class. You asked and we listened by outfitting the 50hp four stroke with a new and improved gear case with a lower gear ratio, giving you the increased low end torque your boat needs.

This outboard also has variable idling speed control from 650 to 950rpm's. And the MFS50's stainless steel water pump housing liner gives you outstanding durability. With the 50hp four stroke's power to quickly reach your destination, exceptional fuel performance to keep gas costs down and proven technology for worry-free boating, you’ve never had a day on the water quite like this.

Tohatsu 4-Stroke Benefits:

  • All new sleek design
  • Outstanding fuel economy
  • Lightest weight in its class, starting at just 209 lbs.
  • Available in short (15") & long (20") shaft lengths
  • Ultra-low 3 star CARB emission approved
  • 5 Year limited warranty

High Performance and Easy Operation:

  • Electronic fuel injection
  • Digital CD ignition system for quicker starts
  • High output 21 amp alternator
  • New and improved gear case with lower gear ratio for increased low end torque
  • Adjustable steering friction and trim tab for reducing steering effort
  • Power trim and tilt

Fundamentals for User Convenience and Reliability:

  • Built-in freshwater flushing system for easy routine flushing
  • Through-the-prop exhaust for a quieter ride
  • Variable idling speed control from 650 to 950 rpm's
  • A camshaft-driven trochoid oil pump ensures long-term durability of critical engine components
  • Stainless steel water pump housing liner for outstanding durability

Warning & Protection:

  • Low oil pressure warning (visual and audible)
  • Overheat warning (visual and audible)
  • Battery voltage warning (visual only)
  • Safety lanyard (an essential protection feature standard on all Tohatsu outboards)
  • Start-in-gear protection for safer engine starting
  • Over-rev. limiter



Engine Control Unit

Multi-Function Tiller Handle

Available on select 25hp models. This handle features an ergonomically designed shift lever for easy and convenient shifting as well as a longer throttle grip with 110 degrees rotation for easier maneuverability. All controls on the multi-function tiller are conveniently located on the handle for easy access and control. The gear shift, throttle control, trim switch, safety lanyard cord and electric start key switch are all integrated in the handle.


Engine Control Unit

Variable Idling System

Allows trolling speed (RPM) to be adjusted in four levels from 650rpm to 950rpm (100rpm each) using the key-switch.


Three step trolling speed control

Built-In Freshwater Flushing System

Standard built-in freshwater flushing system simplifies routine engine flushing.


Three step trolling speed control

Audio Visual Warning System

The tachometer informs the operator of potential problems such as low oil pressure, low battery, and overheat, through the built-in warning lights. (For models equipped with a tachometer)


Three step trolling speed control

Tubular Air-Intake

The tubular structure of the air-intake, originally developed by Tohatsu, helps to take in necessary airflow to the engine while preventing water from entering into the motor cover.


Three step trolling speed control


Standard built-in freshwater flushing system simplifies routine engine flushing.


Engine (No. of Cylinder) 3
Output 50 hp (36.8 kw)
Displacement 866 cc (52.84 cu.in.)
Bore x Stroke 70 x 75 mm (2.75 x 2.95 in)
Starting Electric
Control Type Remote Control or Tiller Handle
Gear Shift Forward - Neutral - Reverse
Gear Ratio 2.08:1
Ignition System MicroComputer Programmed
Transom Height 15", 20"
Fuel Unleaded Gasoline (87 Octane or higher)
Oil Type NMMA Certified FC-W® 4-stroke oil** SAE 10W-30/40 (SF, SG, SH, SJ)
Oil Capacity 0.63 gal. (2.4 L) w/filter
Weight* 209 lbs. (95 kg)
Alternator Output 12V, 252W, 21A
Max. RPM Range 5,000 - 6,000
Electronic Fuel Injection S
Digital CD Ignition System S
Start In Gear Protection S
Thermostat Controlled Cooling System S
Through-The-Prop Exhaust S
Overheat Buzzer S
Oil Pressure Warning S
Power Trim and Tilt S


  • S: Standard Features
  • O: Optional on Certain Models
  • * Weight specification is based on the lightest version.

    ** FC-W® is a registered trademark of the National Marine Manufacturers Assoc. (NMMA)

    Specifications and descriptions are subject to change without notice.



    Parts Book Type Brand Model Book Year Book #
    Download 4-Stroke Tohatsu MFS50A 2014 002-21056-0
    Download 4-Stroke Tohatsu MFS50A 2015 002-21056-0AE

    Request Quote


    Prop Type Load* Diameter Pitch Blades Standard Equip. Part # Comments
    aluminum light 11 17 3   3KYB645360  
    aluminum light 11 16 3   3KYB645340  
    aluminum light 11 15 3   3T5B645320  
    aluminum light 11.1 14 3   3T5B645290  
    aluminum light 10.5 14 4   9999AMT414M  
    aluminum light 11.1 13 3   3T5B645270  
    aluminum moderate 10.5 13 4   9999AMT413M  
    aluminum moderate 10.8 12 4   9999AMT412M  
    aluminum moderate 11.4 12 3   3T5B645250  
    aluminum moderate 11.6 11 3   3T5B645230  
    aluminum heavy 12.1 9 3   3T5B645180  
    aluminum heavy 11.2 8.7 3   348B641071  
    aluminum heavy 11.4 7.1 4   348B641081  
    stainless steel  NA 10.25 17 3   PT4050REBP17  
    stainless steel  NA 10.375 17 3   PT4050SCBP17 semi-cleaver
    stainless steel  NA 10.375 16 3   PT4050SCBP16 semi-cleaver
    stainless steel  NA 10.25 16 3   PT4050REBP16  
    stainless steel  NA 10.5 15 3   PT4050P15  
    stainless steel  NA 10.375 15 3   PT4050SCBP15 semi-cleaver
    stainless steel  NA 10.5 14 3   PT4050P14  
    stainless steel  NA 10.5 13 3   PT4050P13  
    stainless steel  NA 10.5 12 3   PT4050P12  
    stainless steel  NA 10.75 11 3   PT4050P11  

    Repair Kits/Electrics

    Part Number Description
    3T5-87322-3 Water Pump Repair Kit

    Fuel Tanks + More

    Part Number Description
    3H670-2002M Fuel line hose (primer bulb assembly & fuel connectors)
    3FF70-2004M Fuel line hose (no connectors/fittings; fits all models)
    394-70260-0 8mm (5/16") fuel connector (engine male)
    3GR70-2500M 8mm (5/16") fuel connector (engine female)
    99999-37851 Tohatsu Water/Fuel Separator Kit (includes one filter)
    99999-37801 Replacement 10 micron filter (for Tohatsu Water/Fuel Separator)
    99999-UF10K UNIKAS UF-10K Water/Fuel Separator Kit (includes one filter)
    99999-UF10RF Replacement 10 micron filter for Unikas UF-10K (includes replace o-ring)