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You’ve just purchased a new engine. What can you do to ensure you get maximum longevity from it?

Q: You’ve just purchased a new engine. What can you do to ensure you get maximum longevity from it?

A: A boat owner should be able to expect years of dependability and performance from a new, fresh-from-the-box engine. But whether inboard, outboard or sterndrive, how an engine is initially treated will significantly affect the length of its working life.

A proper break-in period is critical for any new engine. And with today’s power plants running leaner and hotter than previous generations, the break-in procedure is more important than ever. More to the point: A few hours of break-in time for an $18,000 engine can protect the investment and keep you from essentially throwing money out the window.

In my 27 years as a marine mechanic I’ve seen just one engine that simply wore out. Most engines, in my experience, never get a chance to wear out. There’s always some preventable circumstance that shortens its life.

Recreational boaters who properly maintain their engines should, in my opinion, get about 2,000 hours from a 2-stroke outboard, up to 10,000 hours from a 4-stroke outboard, 1,500 hours from a gas inboard, and 12,500 hours from a diesel. The key to reaching these numbers begins with the break-in procedure specified by the engine manufacturer, which will include recommendations for rpm intervals, length of time throttling up, and load factor.

Be patient, not foolish. Don’t tow a skier the first time out or run hard to a favorite fishing spot. Vary the throttle to make sure all high-stress surfaces — such as pistons, cylinder walls, rings and bearings — “mate” before really putting a load on. Improperly mated surfaces can lead to oil contamination from the combustion chamber, also known as blow-by; lower engine output, which may or may not be noticeable; and increased or decreased friction, either of which can shorten engine life.

Following break-in, the engine will need its first maintenance schedule. I recommend a low-hour maintenance check (10 to 20 hours) for any new outboard, inboard or sterndrive, including changing the engine and lower unit oils. This also is a good time to determine if any problems have developed. If so, there’s time to correct them before they turn into something major. And, of course, the engine is still under warranty.

I also like to change all fuel filters and fuel-water separators during the first maintenance check. Some people might consider this excessive, but I think it’s worth the cost and effort. Debris from new-boat construction — and water — often ends up in a boat’s fuel during the first 20 hours of operation. (In general, fuel-water separators should be changed each season, twice in year-round boating locales.) Lastly, look for wire chafing, and check all fittings, hoses, connections and fasteners.

I recommend spraying the engine (except for timing belts and the bendix) with a water-dispersing product. I like CRC 6-56 for its staying power. WD-40, by contrast, has a relatively short life.

The more often you flush an engine with fresh water, the better. This obviously refers to outboards, but some inboards now are built with flushing systems.

With outboards in particular, I recommend using a fuel additive to reduce carbon buildup, but be sure to follow the engine manufacturer’s recommendations. Some brands include Ring Free (Yamaha), Carbon Guard (Evinrude/Johnson) and Quick Clean (Mercury).

If you idle your 2- or 4-stroke outboard for long periods, or start and stop it frequently (such as for drift fishing), it’s important to run the engine hard occasionally to clean out the combustion chamber. A fuel additive is especially important for outboards that are used in this manner.

With inboards, make sure the flame arrester stays clean. Dust from belts can collect in the arrester and over time restrict air intake.

A final piece of advice for maximizing engine life: Faithfully adhere to all manufacturer-recommended maintenance schedules.