Background:

In some ways, owning and operating a boat engine is similar to owning any other type of engine. Common sense and regular maintenance will help ensure long life. However, because it operates in the water, your boat engine is different in many ways than the engine in your automobile or garden tractor. Marine engines require specific preventative maintenance procedures. Here are seven “musts” that every boater should practice.

1. Check the gear lube

One of the most important maintenance steps for a new engine is to change the gearcase lube at 100 hours of operation or at the end of the boating season, whichever comes first. This flushes debris or metal grindings from the gearcase that were produced during break-in of the internal components. Quicksilver offers several grades of quality gear lube, plus gear lube pumps and cartridge lube guns.

2. Clean, lubricate, and tighten battery terminals

You turn the key and nothing happens. Before assuming your battery is dead, check the battery terminals for loose or corroded cable clamps. Applying anti-corrosion material to the battery terminals and tightening the cable clamp bolts will help prevent a poor electrical connection. Use a wrench to tighten the clamps. Finger tightening is inadequate.

3. Eliminate water in fuel

Marine engines are made to run in water, but when water finds its way into the fuel system, you could have trouble: hard starting, stalling, maybe even engine damage. A simple way to help prevent these problems is to periodically add fuel treatment (such as Quicksilver Dri-Fuel) to the fuel tank to absorb water in the fuel. For added protection, install a Quicksilver water separating fuel filter kit and replace the filter element at least once each year. For carbureted engine applications, the filter is typically located on the boat. On Mercury/Mariner EFI/DFI/OptiMax engines, the filter is located under the cowling, and it is recommended that no additional filter be installed on the boat.

4. Add fuel stabilizer to the fuel tank

When fuel sits in the fuel tank and other components of the fuel system of your boat, it gets stale. The solvent component of the fuel evaporates, leaving sticky deposits that plug up carburetor passages, freeze floats, and gum up fuel injectors. Any of these gummed up components could prevent starting or proper operation of your engine. To prevent this from happening, add fuel stabilizer (such as Quicksilver Marine Fuel System Treatment and Stabilizer) to the fuel tank, then run the engine for several minutes to allow the stabilizer-treated fuel to circulate throughout the fuel system. This can help eliminate starting and running problems the next time you operate the boat. Always follow directions as listed on the container. In general, there are two different ratios for adding stabilizer: one to protect between occasional uses, and another for long-term storage.

From Mercury Marine's Tournament Angler Support Team

In Part 1 of the Mercury Marine Tech Tips column on preventative maintenance “musts” for your outboard, we detailed the following four procedures: changing the gear lube; cleaning, lubricating, and tightening battery terminals; eliminating water in fuel; and adding fuel stabilizer to the fuel tank. Following are the remaining three maintenance “musts.”

5. Tighten the prop nut

Sometimes when a prop is installed it’s not torqued properly, which simply means the nut holding the prop on is not tightened to the proper degree. A loose prop can cause undue wear on the thrust hub, which positions the propeller on the prop shaft. Given enough time the thrust hub could fail, allowing the spinning prop to strike the gear housing. Prevent this scenario by periodically checking to make sure that the prop nut is properly torqued. Using a torque wrench, torque the propeller nut to the torque listed in your operation and maintenance manual. It’s also a good idea to periodically remove the propeller to check for fish line wrapped around the prop shaft. To prevent the propeller hub from corroding and seizing to the propeller shaft, especially in saltwater, always apply a coat of lubricant to the entire prop shaft at the recommended maintenance intervals and each time the propeller is removed.

6. Lubricate the starter drive and armature shaft

You turn the key and hear the starter motor run, but the engine doesn’t turn over because the starter is not engaged with the flywheel. You may never experience this problem if you periodically perform the following simple preventive maintenance step. Place a drop of lubricating oil (almost any oil will do) on the starter drive and armature shaft.

7. Control corrosion before is starts

There are two types of corrosion that can damage your engine: galvanic corrosion and oxidation, or rust. Galvanic corrosion happens when two dissimilar metals are immersed in water, which causes them to become electrically connected. Unprotected, the aluminum drive components on your engine can be eaten away before you know it. There are several ways to prevent galvanic corrosion.

All Mercury Marine outboards are equipped with sacrificial anodes. Inspect them regularly and replace them when they are approximately 509o eaten away. Never paint the anodes. If your boat is plugged into shore AC power, use a galvanic isolator to prevent stray currents from improper wiring on docks and/or neighboring boats from creating galvanic currents that can damage your outboard. If you have an outboard equipped with a stainless steel prop and your boat stays in the water all the time, consider a “MerCathode” System to protect your investment. The electronic MerCathode produces an electrical field to protect your outboard from galvanic corrosion.

During and after the boating season, simple periodic inspections can detect oxidation problems before there’s any engine damage. For severe saltwater conditions, regularly apply Quicksilver Special Lubricant 101, 2-4-c, or Anti-Corrosion Grease to the prop shaft and other bare metal surfaces to help prevent corrosion. Before end-of-season storage, treat your engine with Quicksilver Storage Seal Rust Inhibitor to prevent internal corrosion. (Also see Long-Term Winterization Tips.) Touch up any paint nicks or scratches with Quicksilver Touch-up Paint. Spray the engine, including wires and connections, with Quicksilver Corrosion Guard.