Mercury 20 HP Electric Start Long Shaft Outboard Motor with Steering

The Mercury FourStroke 20 EL EFI is a 4-stroke outboard marine engine designed for small fiberglass, aluminum, or inflatable boats, 2.5–5 meters in length, that require a long shaft, featuring a 20 HP / 14.7 kW and 333 cc 2-cylinder engine. The FourStroke 20 EL EFI with its 333 cc EFI FourStroke engine offers economical and reliable power to small and medium-sized boat users.

FourStroke 20 EL EFI Series Features and Technology Advantages

The 2-cylinder design provides balanced power with a compact and lightweight design. EFI injection ensures reliable starting without requiring a manual fuel system.

• 2-Cylinder Engine (333 cc): The 2-cylinder design provides balanced power with a compact and lightweight design.
• Long Shaft (508 mm (20")): The propeller operates at optimal depth with the correct transom height.
• EFI Electronic Injection: No primer bulb required — automatic fuel system fill before turning the key.
• Electric Start Manual Operation: Easy starting with low battery consumption; pull cord system as backup.
• Manual Trim: Manual adjustment of transom angle — simple and reliable mechanical structure.
• 12 Liter Internal Tank: Ready for daily short-distance use; external tank input available.

Long Shaft — Which Boat Type Is It Suitable For?

The long shaft (508 mm (20")) is suitable for the vast majority of inflatable boat, aluminum, and fiberglass boat models. For boats with a transom height of 381 mm, a short shaft model should be preferred.

Technical Specifications

Who is This Engine For?

• 2.5–5 meter small and medium-sized boats: economical EFI power.
• Fishing and coastal use: quiet 4-stroke operation.
• Inflatable boats and RIBs: lightweight engine and balanced thrust.
• Auxiliary engine: access to a reliable Mercury service network.

Maintenance and Longevity

4-stroke Mercury engines operate trouble-free for many years with regular oil changes and end-of-season maintenance protocols. The impeller of the water-cooled system should be checked every 100 hours or every two seasons. In saltwater use, freshwater flushing is mandatory after each use.

Related maintenance categories: Maintenance Kit | Engine Oil | Impeller | Mercury Spare Parts

Frequently Asked Questions

What boat size does the Mercury FourStroke 20 HP engine fit?

20 HP of power can fit different sizes depending on the boat's weight and type. General rule: 15–20 kg of boat weight per HP. Always check the maximum engine power recommended by the boat manufacturer.

What advantage does the EFI system offer over a carbureted engine?

EFI (Electronic Fuel Injection) does not require a primer bulb or choke adjustment. It provides reliable starting in cold weather and high altitudes, consistent power output, and lower fuel consumption compared to carbureted alternatives.

What are the maintenance intervals for Mercury FourStroke?

Oil change at the first 20 hours, then every 100 hours or once a season. Impeller check every two seasons. In saltwater use, freshwater flushing is mandatory after each use. End-of-season fuel system protection is recommended.

Which boat and brand models are compatible with the FourStroke 20 EL EFI?

Mercury outboard engines are compatible with many fiberglass, aluminum, and inflatable boat models thanks to their universal transom clamp or transom mounting system. The only criteria are your boat's 508 mm (20") transom height and the maximum engine power approved by the manufacturer. You can get compatibility confirmation from Clever Marin by sharing your boat model.

Related Products and Categories

• Mercury Outboard Engines
• Mercury Marine Products
• Mercury Spare Parts
• Mercury 2.5–30 HP FourStroke
• Mercury 40–60 HP FourStroke
• Outboard Engines
• Boat Engines
• Maintenance Kit
• Impeller
• Anode

Is This the Right Configuration for Your Boat?

Share your boat model, transom height, and intended use — let's confirm together if the Mercury FourStroke 20 EL EFI engine is suitable for your boat and ensure the correct shaft selection.