Buying a Used Outboard Motor

Because of today’s high prices for new outboards, used engines are steadily becoming a lot more attractive to those of us who have limited financial resources. The good news is there are definitely some great buys to be had, provided you do a little homework. So here are some noteworthy pitfalls to avoid when checking out a second-hand kicker. And if you’re not mechanically inclined, consider hiring the after-hours service of an outboard mechanic to assist you because nowadays “used” does not necessarily mean “cheap,” and thus your investment will likely still be significant.

Overall Appearance

Considering that for at least the past decade all major outboard makers have been using primarily corrosion-resistant materials, if it looks like it has been regularly “rode hard and put up wet,” pass. All it takes to keep it looking good is the regular application of a little soap, water, and anti-corrosion lubricant. Saltwater is tougher on engines than fresh, so if it looks bad on the outside it almost certainly hasn’t been maintained internally very well, either. This especially includes regular flushing of the cooling system with fresh water.

Age is certainly a factor, but still I’d be more likely to choose a 3- or 4-year old engine that showed positive signs of good care and maintenance (especially if it met the other criteria listed below) over a 2-year old that looked like the end result of a corrosion experiment gone horribly wrong.

The Powerhead

Remove the cover (be wary if the fit is loose when it is designed to be tight; that could indicate it has been pulled too frequently for repairs and other problems) and visually check for signs of neglect or damage. Blistered paint would indicate serious overheating, for instance. Signs of heavy tool use on bolts and screws are also a warning. Ditto any signs of water leakage around gaskets, especially the white powdery residue that goes with saltwater. And while the cover is off, now is the time to perform the next five steps:

(1) Look for cracked, burned, or otherwise damaged wire insulation, especially where it exits a fitting (e.g. spark plugs, magneto, coils). Ditto insulation repaired with any type of tape. Cracks in the cover of any electrical component are also warning signs.

(2) Pull all spark plugs and check for excessive deposits of any type. Seriously dirty plugs can interfere with the engine’s performance, sometimes enough to cause random misfires that put excessive loads on the crankshaft, connecting rods, and their associated bearings – and eventually cause expensive damage.

(3) Check the ignition system. If you don’t have an ignition tester handy, you can easily make a simple version in a few minutes. When the engine is cranked, each sparkplug circuit should fire with a bright blue spark.

(4) Compression should be within factory limits. Find out the proper cylinder compression levels for the make and model you’re contemplating. All cylinders should be checked with a compression gauge, and if they’re outside these tolerances, give that engine a bye because it almost certainly has had a lot of hard use at excessively high rpms. Even if inside the recommended range, there should be no more than 10 percent variation among all cylinders from the highest pressure reading to the lowest.

(5) The top main bearings should still be reasonably tight. This means there should be no play at all when you grab the flywheel and try to rock it from side to side. Nor should you be able to pull the flywheel upward, either. If the top bearings are loose, this indicates serious wear and you can bet the bottom mains are badly worn too. This alone means you’re looking at a whopper of a repair bill. If both (4) and (5) fail to pass the test, the reality is a new or completely rebuilt powerhead.

Lower Unit

Contrary to popular belief, paint worn off the skeg is not necessarily indicative of abuse. It’s a common result of shallow water operation. BUT a damaged skeg (pieces broken off), bent blade(s) on the prop, and especially a bent shaft should make you very wary. Rebuilding a badly damaged lower unit and gear case is second only to the powerhead in terms of repair cost.

A bent propeller shaft is not always easy to detect by eye, so to be safe it’s a good idea to pull the prop and hold a straightedge against the shaft. Rotate the shaft slowly by hand and look carefully; if there is even a tiny bit of wobble, lower unit seals and bearings won’t last long and it doesn’t take a crystal ball to see that a major repair bill is in your near future.

Loosen the top screw-in plug in the lower unit oil system sufficiently to allow air to seep in, then remove the bottom plug long enough to see if any water comes out with the oil – a sure sign of leaky seals. Even a tiny bit of water is unacceptable. It’s also not a bad idea to strain a little of that oil through a cloth to see if it contains metal particles.

Once water – and especially saltwater – starts entering the gear case it will eventually displace all of the oil. And if it’s there long enough the gears will rust or crystallize and start breaking off teeth. It only takes one loose gear tooth to destroy all the gears.

The Gas Tank

This applies to all outboards, regardless of whether the tank is atop the powerhead, a portable remote, or built into the boat. Take the top off and use your nose to determine if the gas has a “fresh” smell. Use a small flashlight to visually inspect as much of the interior as you can see (a match or cigarette lighter is definitely NOT recommended for this procedure!). Gummy deposits and stale gasoline are sure signs of potential carburetor problems. If the tank is a remote portable, it can simply be replaced. But for an integral tank, expect to add the cost of a steam cleanout to the almost certain cost of an expensive carburetor cleaning/rebuilding job.

Try Before You Buy

The best way is on a boat of suitable size for that horsepower. Lacking that, in a test tank with one of those special props designed for that purpose (at least for engines over 10 hp). It should start easily, idle smoothly, and accelerate all the way to full throttle without missing. And it should pump cool water in good volume without interruption. If buying a big engine, spend a few bucks to have a dealer test it for horsepower output on a dynamometer.

Other Considerations

Is the engine still within warranty? Some manufacturers offer optional extended warranties for up to an additional three years (also definitely a good buy for the current owner contemplating the sale of an engine). If buying used from a dealer, consider the firm’s reputation and also ask about some sort of “dealer warranty” (some offer up to 90 days).

If the engine is a 4-cycle, you should also consider the oil sump in the powerhead since no oil is added to the gasoline for internal lubrication. Is the oil level correct? At least some makes require that the engine be run long enough at a fast idle to be thoroughly warmed up before the dip stick is pulled to check this. And is the oil reasonably clean? Since outboards run on water where the air is a lot cleaner than most roads and streets, the oil tends to stay reasonably clear a bit longer. If it’s really black with dirt and feels gritty when rubbed between the thumb and forefinger, it probably wasn’t changed when it should have been.

And finally, what about the owner’s manual? If the seller doesn’t have it, get one before you close the deal. Check the engine’s specifications and recommended operating procedures. The information contained therein could save you from some unpleasant surprises down the road.

by Bob Stearns

Bob, the editor-at-large for Saltwater Sportsman Magazine and a senior editor for Center Console Angler, has published over 1,600 feature articles and columns in many popular national magazines, such as Boating, Rudder, Motorboat, Field & Stream, Salt Water Fly Fishing and many others. He has also authored several books and appeared on numerous fishing TV programs. As a consultant, he has worked with boat and boating materials manufacturers, and fishing tackle manufacturers on product development and design.

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