Fixing an older outboard engine — what an upgrade means and costs
Is an old outboard motor worth fixing? Join John Ford as he weighs up the pros, cons and risks of upgrading an old engine.
Most of us who have been into boating for a while will face the decision to upgrade the engine at some time. Because, unlike cars, a boat hull can last for many generations if properly maintained, and most of us only use our boats sparingly.
Many pristine old Haineses, Seafarers, Cruise Crafts and more are as serviceable as the day they left the showroom. That might not be the case for the engine, though, as lack of use can be a significant cause of engine failure.
Every summer, boat shops are flooded with customers who took their boat for a run only to find it would not start or that they got 10 minutes into their long-planned family day out only for ‘old reliable’ to splutter to a silent and smoky stop. It can be embarrassing and disappointing, but it can be life-threatening if you are halfway out of a tricky bar.
Many new boaters who have bought a dodgy second-hand bargain where the engine has failed will probably be turned off boating forever. An old hull with a broken engine might be nothing more than an expensive garden ornament.
However, the price of a new outboard can be a barrier to many owners, especially for the higher horsepower options. So, let’s look at refurbishing. What are the pitfalls and costs of restoring an older boat engine, and is it worth the risks?
First though, some background on how we got here. The first commercially available outboard engines saw service in the late-1800s with the American Motor Company's tiny four-stroke. A decade later, Ole Evinrude turned the tide with his portable two-stroke under the name of the Evinrude Detachable Rowboat Motor Company. Thus dawned an era of recreational boating that we know and love. Naturally, things have changed since those slow and smoky outboards were released, and in today’s market, we are spoiled for choice with engines between 2.5 and 600hp. These days, if you look through the catalogues of available outboards, you will notice that virtually every motor is a four-stroke. That’s because laws around emissions, mainly in the US, dealt a death blow to oil-burning two-stroke engines. Evinrude was the holdout, but by 2020, the writing was on the wall, and they, too, shut up shop.
Older engines will separate into four strokes up to 15–20 years old or a range of two strokes going back to the ‘80s. Before committing to major work, some simple issues must first be looked at. All outboards need regular servicing, similar to a car, and reputable marine mechanics will know what needs to be done according to the engine hours and time since the last service. One of the most common problems is overheating, and there could be an easy fix with a new water pump impeller, which is a DIY for many and a relatively cheap fix at your local outboard servicer.
However, if the new impeller doesn't fix overheating or if there are more worrying signs, before committing to a rebuild, there are a few general guides to consider. Most mechanics will tell you that if a boat spends its life on a mooring in salt water and is more than 10 years old, it’s probably not worth the effort to bring it back to new. Salt is the enemy of metal, and engines left in this environment will corrode to the point of failure over time.
But for expert advice on what's worth pursuing and what's best used as a mooring anchor, I settled back for a yarn and a cold one with my local outboard specialist, Stewart Jeffers, at Eden Outboards.
First, Stewart says he always advises against a major rebuild of any engine that will be used on the high seas. “Heading out on open waters or crossing a bar with a suspect engine is high risk, and I don't want to be involved,” he insisted upfront.
He believes older two strokes can be a risk, and unless you are very mechanically skilled, anything pre-1990 will be expensive and time-consuming. A decent mechanic will cost $100–130 and more an hour, and even a simple 5–8hp engine will soak up 5–6 hours plus parts.
The biggest issue with most engines is the electronics. The electrical system is a complex mix of a stator for charging, a trigger for timing and the power pack — often a CDI unit — and any of these can fail at any time in an older engine, and it can take an extended time to diagnose a problem. But if the motor is ceased, then forget it.
Jeffers reckons it’s a waste of time persisting with any ‘80s Mercury two strokes. They suffer from ignition failures that are notoriously hard to diagnose.
The later Optimax two-stroke was an absolute powerhouse across the range, with many owners clocking up hundreds of trouble-free hours. But they are a very complex design with many parts, so it can be challenging to find the cause when they play up, and parts can be expensive. The fuel system has direct injectors with high-pressure pumps in the best tradition of the last hoorah for two-cycle engines. But the chase for efficiency, power and low emissions had a price. The V6 fuel system had a lift pump, low- and high-pressure pumps, six direct injectors and six electronic injectors fed by a compressor on the rail. Experienced Mercury mechanics got it down pat but working it out yourself from a workshop manual will see you burning the midnight oil and leaving the kids to wonder if their favourite parent left home.
Over at Evinrude, the ‘90s FICHT engine sent the company broke, and a rebuild on one of these would be a challenge. The new company owner Bombardier introduced the E-TEC, and while they were immensely powerful, reliability has proven an issue for some models. Others have immense hours of use. A significant consideration with working on an E-TEC is that only authorised dealers can access the right computerised diagnostic tools, so problem-solving is guesswork for the home mechanic. Common and almost unsolvable failures include oil pumps, fuel injector failure and the ECU dying.
Inherent drawbacks aren't confined to two strokes, however. When four strokes were brought to market, they battled weight, and some manufacturers removed metal from water galleys, barrels and cylinder heads. This caused corrosion in the engine, which had dealt an early death to many pre-2010 Japanese four-stroke outboards.
Have we put you off breathing life back into your old donk? Good news, there might be hope for some classic outboards. Generally speaking, later 150hp engines from Yamaha and Mercury have a blessed lifespan with a robust gearbox and reliable power, so a high-hour example is worth saving. In the two-stroke world, the 70hp Yamaha from around 2010 is a simple oil-injected workhorse that a competent home mechanic could have some fun with, and from that same period, the 15hp Mercury is relative child's play compared to many we could name.
Deciding whether to fix up an old, tired engine best comes down to cost and how much enjoyment you hope to experience. If working on mechanical marvels floats your boat, you can save some dollars and have some fun working the Lazarus magic. But we must think again if it risks lives at sea with a dodgy rebuilt engine.
THE NEXT STEP
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