The Mercury Marine FAQs You Need to Know

The Mercury Marine FAQs You Need to Know

Mercury Marine has worked hard to innovate to make world-class outboards for over 75 years. Starting in a small shop in Wisconsin with faulty Thor Outboards in 1939, E. “Carl” Kiekhaefer, earned the legacy that is now the largest builder of marine propulsion systems in the world.

Mercury Marine continues to set the standards for reliable, trouble-free performance. If you have a Mercury outboard or are considering purchasing one, there’s important information you need to know for the ultimate ownership experience.

Outboard Care

Can I start my engine momentarily out of the water?
No. NEVER start or run your outboard motor without water circulating through the cooling water intake in the gear case. Cooling water prevents damage to the water pump (running dry) and overheating of the engine.

How often should spark plugs be changed?
Every 300 hours or 3 years, whichever comes first.

Where can I get factory Service manuals, Parts manuals, or Operation, Maintenance & Warranty manuals?
You can order all available literature through us here at Online Outboards, an authorized Mercury dealer.


How do I register my engine with Mercury, to ensure that it has warranty coverage?
If you purchased your Mercury Marine motor from Online Outboards, we’ll process the warranty registration on your behalf.

Outboard Storage

What should be done when storing boats with ethanol-blended fuels for extended periods?
Follow the instructions for normal storage preparation found in the Operation, Maintenance & Warranty manual. When preparing to store a boat for extended periods of two months or more, it is best to completely remove all fuel from the tank. If it is difficult or not possible to remove the fuel, maintaining a full tank of fuel with a fuel stabilizer added to provide fuel stability and corrosion protection is recommended. It is best to add the stabilizer and fuel treatment to the tank at the recommended dosage, run the engine for 10 minutes to allow the system to be cleaned, shut off the fuel valve to interrupt the fuel supply, and allow the engine to run until it stops, then top off the tank until it’s full to reduce the amount of exchange with the air that might bring in condensation. Do not cap the tank vent and do not fill with fuel to the point of overflowing. Some extra space should be maintained in the tank to allow for expansion and contraction of the fuel with temperature changes. A partially full tank is not recommended because the void space above the fuel allows air movement that can bring in water through condensation as the air temperature moves up and down. This condensation could potentially become a problem.

Mercury Marine Quickstor can help maintain fuel systems in storage. Quickstor contains oxidation inhibitors to reduce oxidation and gum formation, metal-chelating agents to protect metal components from corrosion, and water-absorbing agents to reduce the presence of free water.

Should I shrink-wrap my boat before storage? If so, are there any items affecting my engine that I should be concerned about?
Shrink-wrap is a very effective method of protecting the boat during periods of storage; however, it is very important to ventilate the hull. Even in the driest conditions, without ventilation, the plastic cover will trap moisture. This moisture can create rust on some metal components, corrosion on others and mold/mildew on the carpet and upholstery. Always follow the manufacturer's recommendations for ventilation.


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