RX: Long Life - Outboard Maintenance

By Bruce W. Smith

Low-tech maintenance is needed for today's high-tech, four-stroke outboards.

Technological advances have made life so much easier than it was just a decade ago when it comes to maintaining our tow vehicles.

Batteries are maintenance-free, fan belts and spark plug's are good for 100,000 miles, sealed bearings never need greasing, special radiator coolants never need replacing, and even oil changes can exceed 10,000 miles. You basically drive and forget.

Unfortunately, there are a lot of boaters who view four stroke outboards the same way and they snooze right through anything related to preventive-maintenance. That type of attitude is a fast track to shortening the life of a very expensive outboard.

Break Out The Drain Pan

A four-stroke outboard should get a thorough cowl-to-prop service once a year — more if you log a lot of hours on the water. That basic four-stroke maintenance begins with a critical oil change around 20 hours-or whatever time period your owner's manual recommends. This is the break-in period when the oil basically flushes the engine of any normal wear particulates that may have been left during the building process. Changing the oil and filter every 100 hours, or once a year, whichever comes first, is usually sufficient from that point on.

Changing the oil is simple: read the owner's manual and follow the steps. The brand of oil is not a major concern as long as it meets Society of Automotive Engineers (SAE) viscosity grade, as well as the American Petroleum Institute (API) and International Lubricant Standardization and Approval Committee (ILSAC) performance levels as specified in your outboard's owner's manual.

The Greasy Touch

A good grease job, using a small grease gun kit, is next. Use high-quality marine grease designated as "water-proof" or "water-resistant." There are a lot of pivot points on an outboard. Check and lube each one until a little of the old grease oozes out. Use a towel to wipe up the excess grease. It's also good to put a dab of grease on all the shift and throttle linkages to extend the life of the moving parts. It also makes shifting and throttle control smoother.

Pull the propeller off, grease the splines and remove any fishing line that might be wrapped around the shaft at the seal. (Monofilament has a nasty habit of cutting into the seal, which, in turn, will allow water into the gear case.)

Full Lube Job

While you're at the lower unit, change the gear lube. This is another preventive maintenance issue critical in that first 20 hours the engine is ran.

That's because "high spots" on the gears get worn down during that time, leaving a little bit of metal floating around in the gear oil. Remove the drain plug, drain the oil, refill according to your service manual, and clean off the drain plug magnet before reinserting.

Changing the gear case oil is not a big chore on smaller outboards. But the V-6/V- 8 four-strokes are a much bigger mess that's best left to the dealer.

Dealers usually charge around a $100- $125 to perform an oil change and to fill the gear case with fresh lube. The dealer is also the one to replace the water pump if the engine is more than two years old, and to handle any valve adjustments that may be required.

The rubber vanes will take a set and loose their effectiveness after a couple years, and running an outboard in muddy water or where sand is kicked up accelerates the wear on the impeller.

Fuel System Service

Don't forget the fuel system. Replace the fuel filter and the water/fuel separator filter if your outboard has one. The latter looks a lot like a little oil filter-type cartridge with a paper element inside the canister.

This filter's job is to catch water, so, if you see water in it don't be alarmed-it means the system is doing its job protecting the fuel system. When you replace the filters, write the date on them with a permanent felt marker so a year from now you know it's time to change them again.

Fuel Stabilizers

Even though today's fuel-injected four-stroke fuel systems are very state-of-the-art, it's a good idea to always add some fuel stabilizer and conditioner to the fuel tank. A good routine is to add fuel stabilizer to every tank of gas-mixed, of course, according to the directions on the container. Fuel conditioners prevent moisture build up, a problem that many see during the summer in regions where the humidity is high. Water in the fuel isn't a good mix. Another benefit of a fuel stabilizer/conditioner is it helps gasoline retain its octane rating even after it sits in the tank for two or three months. When the octane starts going south, especially in the heat and humidity of summer, it begins to form a varnish that gums up the fuel filter.

Clean And Protect

Once the lubrication/fuel aspects are addressed, use a garden hose to mist the powerhead to clean it off. After the engine is dry, coat the powerhead with a light coating of a protectant/lubricant such as LPS HardCoat Corrosion Protectant or Boeshield T-9. Your local boat dealer probably has LPS and or Boeshield sitting on the shelf. That's it. An hour spent taking care of your outboard goes a long way when it comes to keeping your time on the water trouble-free and those operating costs minimized.