Mercury 20

i
Welcome Aboard!
Proper care and maintenance is an important part in keeping your Mercury Product operating at peak
efficiency for maximum performance and economy. The enclosed Owner's Registration Card is your key
to trouble‑free family fun. Refer to your Operation and Maintenance Manual for full details of your warranty
coverage.
Details of your nearest dealer can be found on www.marinepower.com where country maps and full
contact information are displayed.
Is your engine properly registered for warranty purpose? Please check on www.marinepower.com. If
necessary, please contact your local dealer.
Declaration of Conformity
If the outboard motor’s serial number plate contains the CE mark in the lower left‑hand corner, the
following statement applies:
This outboard motor manufactured by Mercury Marine, Fond du Lac, WI, USA or Marine Power Europe
Inc. Park Industriel, de Petit‑Rechain, Belgium complies with the requirements of the following directives
and standards, as amended:
Recreational Craft Directive: 94/25/EC
Owner's manual (A.2.5) ISO 10240
Handling characteristics (A.4) ISO 8665
Outboard engine starting (A.5.1.4) ISO 11547
Fuel tanks (A.5.2.2) ISO 13591; ISO 8469
General steering system ABYC P‑17
Safety of Machinery Directive 98/37/EC
Principles of safety integration (1.1.2) EN 292‑1; EN 292‑2; EN 1050
Noise (1.5.8) ICOMIA 39/94
Vibration ICOMIA 38/94
Electromagnetic Compatibility Directive 89/336/EC
Generic emission standard EN 61000‑6‑3
Generic immunity standard EN 61000‑6‑1
Vehicles, boats and internal combustion
engine driven devices ‑ radio disturbance
characteristics
SAE J551 (CISPR 12)
Electrostatic discharge testing
EN 61000‑6‑2; EN 61000‑4‑2; EN
61000‑4‑3
This declaration is issued under the sole responsibility of Mercury Marine and Marine Power Europe.
© 2005 Mercury Marine 20/25 90-10112060 505

Mercury 20 Specifications

General

Exhaust	Through Prop
Starting	Manual
Steering	Tiller
Shaft Length	15"
Horsepower	20 HP

Summary

Declaration of Conformity

Recreational Craft Directive

Specifies standards for Recreational Craft Directive (94/25/EC).

Safety of Machinery Directive

Specifies standards for Safety of Machinery Directive (98/37/EC).

Electromagnetic Compatibility Directive

Specifies standards for Electromagnetic Compatibility Directive (89/336/EC).

WARRANTY INFORMATION

Transfer Of Warranty

Details the process and requirements for transferring the limited warranty to a new owner.

Warranty Registration United States And Canada

Explains how to register your product for warranty coverage in the US and Canada.

Warranty Registration Outside The United States And Canada

Outlines the warranty registration process for customers outside the US and Canada.

Outboard Limited Warranty United States, Canada and Europe

Covers defects in material and workmanship for new outboards in the US, Canada, and Europe.

Outboard Limited Warranty (Confederation of Independent States, Middle-East, and Africa

Details the limited warranty for outboards in CIS, Middle-East, and Africa.

GENERAL INFORMATION

Lanyard Stop Switch

Explains the function of the lanyard stop switch for engine shutdown in emergencies.

Protecting People In The Water

Safety advice for preventing injury to people in or near the water while operating the boat.

Impact With Underwater Hazards

Precautions for avoiding damage and injury from striking underwater obstacles.

INSTALLATION

Installing Outboard

Step-by-step instructions for mounting the outboard onto the boat's transom.

Battery Installation - Electric Start Models

Guidance on mounting and connecting the battery for electric start models.

FUEL & OIL

Fuel Recommendations

Details on recommended gasoline types, octane ratings, and oxygenate content.

Oil Recommendation

Specifies the recommended NMMA certified TC-W3 2-Cycle outboard oil.

Mixing Fuel and Oil

Instructions and charts for mixing gasoline and oil for the engine.

OPERATION

Pre-Starting Check List

Essential checks to perform before starting the outboard engine.

Engine Break-in Procedure

Detailed instructions for the initial break-in period of the engine.

Starting The Engine - Tiller Handle Models

Procedure for starting the engine on tiller handle models.

Starting The Engine - Electric Start Remote Control Models

Procedure for starting the engine on electric start remote control models.

Emergency Starting

Procedure for starting the engine using a spare starter rope if the system fails.

MAINTENANCE

Inspection And Maintenance Schedule

Detailed schedule for routine inspections and maintenance tasks.

Flushing The Cooling System

Procedure for flushing the outboard's cooling system with fresh water.

Propeller Replacement

Step-by-step guide for safely removing and installing a new propeller.

Spark Plug Inspection And Replacement

Instructions for inspecting, gapping, and replacing spark plugs.

Carburetor Adjustments

Lubrication Points

Gearcase Lubrication

Procedure for checking, draining, and refilling the gearcase lubricant.

STORAGE

Storage Preparation

TROUBLESHOOTING

Starter Motor Will Not Crank The Engine (Electric Start Models)

Lists possible causes for the starter motor not cranking the engine on electric start models.

Engine Will Not Start

Common reasons why the engine fails to start, including fuel and ignition issues.

Engine Runs Erratically

Performance Loss

Battery Will Not Hold Charge