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Outboard Engine – Fits Yamaha F70 70hp 4-Stroke (Replaces F70)

Regular price $34.50

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Orders are typically processed within 1–2 business days.


U.S. orders usually arrive within 6–15 days, depending on stock location and destination.


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If you have any questions, feel free to email us at info@sierramarines.com, and we’ll get back to you within 20–36 hours.

Product Details

The Yamaha F70 is a 70hp 4-stroke outboard engine featuring a lightweight, 16-valve, SOHC in-line four-cylinder design. Engineered for responsive power and efficiency, the Yamaha 70hp 4-Stroke Outboard Engine F70 is an ideal motor for a wide range of marine applications, known for its excellent power-to-weight ratio and reliable performance.

This engine serves as a powerful and durable heart for any compatible vessel, offering a blend of modern technology and robust construction.

  • Features Electronic Fuel Injection (EFI) for optimal fuel induction and efficiency.
  • Lightweight design at only 253 pounds for its class.
  • Equipped with a freshwater flush device for easy maintenance and extended engine life.

Technical Specs

Product Type
4-Stroke Outboard Motor
Engine Type
16-Valve, SOHC In-Line Four Cylinder
Displacement
996cc (60.8 ci)
Bore x Stroke
65 x 75mm (2.56 x 2.95 in)
Full Throttle RPM Range
5300 ~ 6300 rpm
Horsepower Rating
70hp at 5800 rpm
Compression Ratio
9.4:1
Fuel Induction System
EFI (Electronic Fuel Injection)
Alternator Output
15 Amp / 17 Amp
Weight
114 kg (253 lbs)
Recommended Fuel
Regular Unleaded (Minimum Octane 87)
Recommended Fuel Filtration
Yamaha 10-Micron Fuel/Water Separating Filter (external)
C.A.R.B. Rating
3-Star
Exhaust
Through Propeller
Intake
16 valves
Ignition
TCI Microcomputer
Spark Plug
LKR7E
Starting System
Electric
Lubrication
Wet Sump
Engine Oil Capacity
2.1/1.9L (2.2 qt with filter)
Recommended Cooling
Thermostatic Control
Ethanol Blend Limit
10% Maximum
Gear Ratio
2.33:1
Gear Shift
Forward, Neutral, Reverse
Shaft Length
20"
Degree of Tilt
65°
Degree of Trim
-4° through +16°
Steering Angle (maximum)
40° from center, either direction
Warranty
Limited 3-year Pleasure, 3-year Government, 1-Year Commercial

Installation Notes

  1. Ensure the transom is rated for the engine's weight and horsepower. Disconnect the battery before beginning installation.
  2. Securely mount the outboard engine to the boat's transom using the provided hardware and tighten to manufacturer torque specifications.
  3. Connect the fuel line from the tank to the engine. Ensure all connections are secure to prevent leaks.
  4. Attach the steering link rod and control cables for throttle and shift. Verify smooth operation.
  5. Connect the main wiring harness to the boat's controls and the battery cables to the battery (positive first, then negative).
  6. Install the propeller, ensuring the hub is correctly seated and the nut is torqued to specification.
  7. Check all fluid levels (engine oil, gearcase lube) before the first start.
  8. Use the freshwater flush port to prime the cooling system before starting the engine for the first time.

Troubleshooting & FAQ

What makes the F70 motor so lightweight?

The Yamaha F70 achieves its class-leading lightweight design through features like a two-piece upper case, which saves weight without sacrificing durability, and an overall compact SOHC in-line four-cylinder engine configuration.

How does the fuel injection system improve performance?

The Electronic Fuel Injection (EFI) system provides precise fuel delivery to the engine, resulting in better fuel efficiency, easier starting, and smoother, more responsive throttle control across the RPM range.

What is the Variable Trolling RPM Switch (VTS®)?

VTS is an optional feature that allows you to adjust the engine's trolling speed in 50-rpm increments, from 620 to 900 rpm. This provides precise speed control for fishing and other slow-speed maneuvers.

What type of fuel and oil should I use?

The engine is designed to run on regular unleaded gasoline with a minimum octane rating of 87. The ethanol blend should not exceed 10%. For oil, use a quality marine-grade engine oil as specified in your owner's manual. The engine has a wet sump lubrication system.

What are signs that my outboard needs service?

Common signs include difficulty starting, rough idling, reduced performance, unusual noises or vibrations, and visible leaks of fuel or oil. Regular maintenance, including checking the on-engine water separating fuel filter, is critical for longevity.

How often should I flush the engine?

It is recommended to flush the engine with fresh water after every use in saltwater or brackish environments to prevent corrosion and extend engine life. The built-in freshwater flush device allows for easy flushing without needing to run the engine.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

Shipping speed & cost

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

Warranty & returns

Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.

Safety & Important Info

  • Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
  • This is an aftermarket replacement, not an OEM component.
  • Professional installation is recommended for safety and performance.

About Sea Sierra

  • Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
  • Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
  • Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.

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