YAMAHA 620-1423A-73 Outboard Jet 2-STROKE 40HP 50HP 112.5

( Manufacturer Part Number: 620-1423A-73 ), ( Part Type: Jet ), ( Country Of Origin: United States ), ( Manufacturer Warranty: Unspecified Length ), ( Storage Location: K1 Roc3-n Buk 44 Bin 6 )

Review YAMAHA Outboard 2-stroke 40hp 50hp Main Jet #112.5 fits 1984–2006

The **Yamaha 620-1423A-73** is a classic and highly sought-after outboard motor from Yamaha s legendary 2-stroke series, produced between **1984 and 2006** under the **40HP (50HP jet)** designation (with a **112.5-inch** shaft length). This engine represents a refined blend of Yamaha s engineering precision and the raw power of its iconic two-stroke design, making it a favorite among boating enthusiasts, collectors, and performance-driven anglers. Built to deliver unmatched acceleration and smooth operation, the **620-1423A-73** features a **40 horsepower** (measured at the shaft) but delivers a **50 horsepower jet** rating, meaning it provides a significant thrust boost when paired with a jet drive or when used in high-performance applications like wakeboarding or racing. The **112.5-inch shaft length** ensures compatibility with a wide range of boats, from mid-sized fishing vessels to high-performance wake boats, offering versatility without sacrificing performance.

Under the hood, this outboard houses Yamaha s **two-stroke, air-cooled, single-cylinder** design, which was renowned for its simplicity, reliability, and explosive power. The **direct-injection fuel system** ensures efficient combustion, while the **pressure-lubricated crankshaft** and **hypoid gear reduction** provide durable, high-torque delivery critical for quick acceleration and handling. The **cast-aluminum cowling** not only houses the engine components but also contributes to the motor s sleek, vintage aesthetic, a hallmark of Yamaha s mid- 80s to early 2000s outboard lineup. This model also incorporates **Yamaha s legendary "Power Head" design**, featuring a **titanium valve spring** and **forged aluminum piston**, which together enhance durability and performance under heavy loads.

One of the standout features of the **620-1423A-73** is its **adjustable trim and tilt mechanism**, allowing for precise control over the boat s ride height and angle, whether cruising at high speeds or maneuvering in tight spaces. The **electric start** (available in later models) and **manual recoil starter** (on earlier versions) provide convenience and reliability, ensuring the engine fires up quickly and consistently. The **jet drive compatibility** of this 40HP/50HP jet-rated motor makes it particularly well-suited for boats equipped with **Yamaha s jet propulsion systems**, offering superior handling, reduced drag, and an exhilarating ride. Whether used for **fishing, racing, or recreational boating**, this outboard delivers a perfect balance of power, responsiveness, and classic Yamaha craftsmanship.

For collectors and restorers, the **620-1423A-73** holds significant appeal due to its **vintage design** and **proven reliability**. Yamaha s **two-stroke engines** from this era are celebrated for their **high-revving nature**, **quick throttle response**, and **distinctive exhaust note**, which adds to their charm. While modern outboards have shifted toward four-stroke technology for emissions compliance, the **620-1423A-73** remains a testament to Yamaha s golden age of outboard innovation a period when performance and simplicity reigned supreme. With proper maintenance, including **regular oil changes, spark plug adjustments, and carburetor tuning**, this motor can continue to deliver **decades of service**, making it not just a piece of boating history, but also a **practical and exciting choice** for those who appreciate the thrill of a well-tuned two-stroke. Whether used on a classic fishing boat, a high-performance wakeboard rig, or a restored classic, the **Yamaha 620-1423A-73** embodies the spirit of Yamaha s legacy **power, precision, and pure driving pleasure**.

### Yamaha 620-1423A-73 (1984 2006) Outboard Motor: Pros and Cons

#### **Overview**

The Yamaha 620-1423A-73 is a 2-stroke, 40 50 HP outboard engine (depending on model year) designed for jet drives and small boats. It was produced between 1984 and 2006 and was part of Yamaha s line of compact, high-performance outboards. Below is a detailed breakdown of its advantages and disadvantages.

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### **Pros**

1. **Compact and Lightweight**

- The 620 series is designed for smaller boats, particularly those with jet drives (like the 112.5-inch model). Its compact size makes it ideal for personal watercraft, small fishing boats, or boats with limited storage space.

2. **Reliable 2-Stroke Design**

- 2-stroke engines from this era were known for their simplicity and power-to-weight ratio. The Yamaha 620 was engineered to deliver strong acceleration and smooth operation, making it suitable for recreational use.

3. **Jet Drive Compatibility**

- This engine was specifically designed to work with Yamaha s jet drives, which were popular in the 1990s and early 2000s for their maneuverability and shallow-water capabilities. The 112.5-inch model is a common fit for personal watercraft or small boats.

4. **Affordability**

- Used 620 engines are relatively inexpensive compared to modern outboards, especially if you find one in good condition. This makes it an attractive option for budget-conscious buyers.

5. **Proven Performance**

- Yamaha s reputation for quality and durability extends to this model. Many owners report that with proper maintenance, these engines can last for thousands of hours, especially if they were well cared for.

6. **Easy to Find Parts**

- As a Yamaha, parts are widely available, and the engine s design is straightforward, making repairs and maintenance more accessible than with some modern outboards.

7. **Good for Recreational Use**

- If you re looking for an engine for casual boating, fishing, or personal watercraft, the 620 can provide adequate power and fun without the complexity of larger outboards.

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### **Cons**

1. **Environmental Concerns**

- 2-stroke engines like this one are known for their oil consumption and emissions. They mix oil with fuel, which can lead to oil leaks and environmental pollution. Modern regulations have made 2-stroke engines less common, and some marinas or lakes may have restrictions on their use.

2. **Higher Maintenance Requirements**

- 2-stroke engines require more frequent maintenance, including regular oil changes (often after every few hours of use) and thorough cleaning of the exhaust system to prevent carbon buildup. This can be time-consuming and costly over time.

3. **Fuel Inefficiency**

- 2-stroke engines are less fuel-efficient than modern 4-stroke outboards. They consume more fuel and produce more waste, which can be a drawback for frequent or long-duration use.

4. **Limited Power for Larger Boats**

- At 40 50 HP, this engine is not suitable for larger boats or heavy loads. It s best suited for small boats, jet drives, or personal watercraft. Attempting to use it on a larger vessel could lead to poor performance or damage.

5. **Outdated Technology**

- Modern outboards feature advanced electronics, fuel injection, and emissions controls that improve performance, reliability, and environmental friendliness. The 620 lacks these advancements, which can make it less efficient and more prone to issues over time.

6. **Potential for Wear and Tear**

- Engines from this era may have accumulated wear over the years, especially if they were not properly maintained. Buying a used 620 requires careful inspection to ensure it s in good working condition.

7. **Restrictions on Use**

- Some bodies of water or boating regulations have phased out or restricted the use of 2-stroke engines due to environmental concerns. Before purchasing, check local regulations to ensure the engine is legal for your intended use.

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### **Conclusion**

The Yamaha 620-1423A-73 is a solid choice if you re looking for a compact, reliable, and affordable outboard for small boats or jet drives, particularly for recreational use. Its simplicity and proven performance make it a practical option for casual boaters or those working with limited budgets. However, its environmental drawbacks, higher maintenance needs, and outdated technology mean it may not be suitable for frequent or heavy-duty use. Additionally, its limited power makes it unsuitable for larger boats.

If you prioritize environmental compliance, fuel efficiency, and modern conveniences, a newer 4-stroke outboard would be a better long-term investment. But if you re looking for a budget-friendly, fun engine for a small boat or personal watercraft and are willing to manage its maintenance and environmental considerations, the Yamaha 620 can be a great fit.

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### **Recommendation**

- **Buy it if:** You need a reliable, low-cost engine for a small boat or jet drive, are willing to handle its maintenance, and don t mind its environmental drawbacks. It s ideal for occasional use, fishing, or personal watercraft where power isn t a major concern.

- **Avoid it if:** You plan to use the engine frequently or on larger boats, prioritize fuel efficiency or environmental compliance, or want the latest technology and reliability. In such cases, a modern 4-stroke outboard would be a more practical choice.

- **Before purchasing:** Inspect the engine thoroughly for signs of wear, leaks, or damage. Check the service history to ensure it has been well-maintained. Also, verify local regulations to confirm the engine is legal for use in your area. Consider whether you re willing to invest in regular maintenance to keep it running smoothly.

Details:

The image to watch on YouTube. Fits: Fits various Yamaha 2-stroke outboard motors, primarily 40HP and 50HP model's, manufactured between 1984 2006. Spotlight: A Day Inside . It is a crucial component for fuel delivery in compatible Yamaha outboard engines.

This is a new OEM Yamaha carburetor main jet, size #112.5, part number 620-1423A-73. Yamaha Cruisers.

part #: 6201423a73 prices

• $5.00-$24.99

specifications ouboaen:

• for makes: Yamaha
• for years: 1984-2006
• mpn: 620-1423a-73
• part type: Jet
• country of origin: United States
• manufacturer warranty: Unspecified Length
• storage location: K1 Roc3-n Buk 44 Bin 6

payments ouboaen:

• wallet: Apple-pay
• credit card: Discover
• other

general ouboaen:

• Boat Parts > Outboard Engines Components > Intake Fuel Systems
• condition: New other see details

returns ouboaen:

• time: 30 Days
• paid by: Seller
• policy: Returns Accepted

seller ouboaen:

• # reviews: 209180
• city: Odessa, Florida
• rating: 99.3%

offer ouboaen:

• availability: In Stock
• best offers: True
• quantity: 1
• options: Ship-to-home
• started: February 8, 2026
• sold: 0

shipping ouboaen:

• service: USPS Ground Advantage, USPS Priority Mail, FedEx 2Day, Overnight
• class: Standard, Expedited, One-day
• cost: $0.00
• type: Fixed
• transit: 5-11 Days
• carrier: USPS, FedEx

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