The total cost for purchase and installation of a new twin, four-stroke outboard system and all associated parts would make a decent year’s wages for many folks. That revelation makes for a powerful incentive to get as many hours as possible out of new power plants.
During my years of chartering, I have had a half-dozen outboards fail on the water, and in a couple of instances, it was quite spectacular — the engines blew chunks! There were several other engines, or powerheads, that I replaced just because I knew they were near the end of their lifespan.
Through all of this, I have developed methods for increasing the useful lifespan of outboards. Knowledgeable input from a sales and maintenance shop is valuable, so I called Jim Hatch at Schock Boats in Newport Beach. Schock Boats is a flagship dealer for Yamaha. It sells and services a great number of engines. Here are our combined thoughts.
Engine longevity begins with selecting the right engine package for your boat. Underpowering will put force the engines to run under extreme loads constantly, which will burn them out sooner. Select an engine package that will provide plenty of power even when the boat is fully loaded with people, gear, fuel and fish.
The break-in period is a crucial time. The key to prolonged life is to carefully follow the engine manufacturer’s instructions for break-in. Use additional oil in two-stroke engines, as recommended in the manual. Whether it’s a two-stroke or four-stroke engine, begin with low RPM for the hours specified — and be sure to vary those RPMs, to guard against constant use wear patterns on the inside of those fresh cylinder walls.
The first service should be done at 10 to 20 hours. The lower leg unit should be drained and replaced, to remove metal dust and shavings. Some manufacturers magnetize drain plugs to attract and hold metallic particles. Keep all oil and lubricant clean, and the engine will last much longer.
Having just spent a life’s savings on an outboard package, it would make little sense to use cheap oils. Advertisements claim that viscosity doesn’t break down over reasonable time. That may be true, but additives in the oil may suffer over time. In the case of four-stroke engines, change the oil and filter every 50 to 100 hours, according to the manufacturer’s recommendations.
If a boat sits in a driveway all year and has nowhere near 50 hours on it, change the oil anyway because oil additives can become acidic. For two-stroke engines, use quality oil with helpful additives. I always use the manufacturer’s brand, because doing so would eliminate any discussions about whether I was using inferior products.
Feed that engine clean fuel by replacing fuel filters often to remove contaminates and water. A fuel additive is helpful, especially in two-stroke engines, to keep the combustion chamber clean of gooey, tarry carbon deposits. Such deposits build up on piston heads and rings. The oily goo is warm when the engine is running, but hardens when the engine is off. When the engine is started, the rings have to pull free from the sticky goo, and that robs engine longevity.
Flush the engine with fresh water and an occasional additive such as Salt Away to remove internal salt residue. Flushing an engine is extremely important if a boat is going to sit for a while. An engine that is started and run nearly daily doesn’t tend to build up the dreaded internal salt residue as quickly.
How an engine is run helps determine how long it will last. Remember that heat is the enemy of an engine, and running at lower RPMs will minimize heat buildup. Adjust the boat’s load, engine trim and trim tabs to give the most comfortable ride at the lowest possible RPMs. Resist the temptation to hammer down the throttle when powering up onto the step. Allowing the power curve of the engine to do its work is the best way to get up on the step without undue heat buildup.
I don’t know how we could get your outboard to outlast your mortgage, but we can work on getting 3,000 hours out of your outboard package. When the time finally comes that the engine needs replacement, give some thought to whether to buy a whole new engine or replace the powerhead. If your lower engine leg has been properly taken care of and is in very good shape, and if the electronics (wiring, harness, etc.) are healthy, then it would make sense to replace the powerhead, which will be considerably less expensive than a new outboard package.
— Capt. David Bacon operates WaveWalker Charters and is president of SOFTIN Inc., a nonprofit organization providing seafaring opportunities for those in need. Visit softininc.blogspot.com to learn more about the organization and how you can help.