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Your route to repowering

There are pros and cons, but there’s one certainty: a new outboard can be your ticket to a better ride

Matt Herum had outgrown his 16-foot skiff. The 15-year-old wanted to spearfish with his buddies offshore, so his dad, Al, put the flat-bottomed Sundance up for sale.

Paul Jutras repowered his 22-foot 1980 Boston Whaler Outrage with a 200-hp Evinrude E-TEC, a DFI 2-stroke.

Herum planned to buy his son a larger boat after the skiff sold, but months passed without serious bites. He found a 20-foot 1974 SeaCraft and made an offer that included the seller taking the Sundance.

“It’s a classic [the SeaCraft], but it was in terrible shape and needed a lot of work,” says Herum, 51, of Tavernier, Fla. “It was going to be complicated and expensive, and there was no way of getting around the modifications.”

Repowering the SeaCraft would certainly be the most expensive part of breathing life into the deep-vee center console. (They made some money for the project by selling the mid-1990s 130-hp 2-stroke it came with.) The rotting transom had to be rebuilt, and the fuel tank and fuel lines needed replacing. To accept a heavier 4-stroke, Herum would have to lighten the load aft as much as possible or deal with performance problems and safety issues.

“Too much weight in the stern would lead to trouble getting on plane and water coming in through the in-deck scuppers,” says Herum. “To fix it we’d likely have to add trim tabs.”

Despite the challenges, repowering is often a more affordable alternative to buying a new boat, especially in these tough economic times. A fiberglass boat almost always outlives the engine. That goes for outboards and inboards.

If your engine is taking its last breath but the boat still has many nautical miles to go, then you might want to consider repowering, which also makes sense if you’re dissatisfied with your boat’s performance. You might want greater speed, better fuel economy, lower noise or less smoke. And let’s not forget the warranty that comes with a new engine. Most outboard manufacturers offer a standard three-year warranty for recreational use.

2-stroke to 4-stroke

Repowering a boat that’s had a 2-stroke outboard with 4-stroke technology can take considerable time and money. And cases like Herum’s warrant major modifications to the hull. Although engine manufacturers have slimmed down their second generation 4-strokes, they still weigh quite a bit more than 2-strokes. The Herums’ 2008 Suzuki DF140 weighs 410 pounds, compared to 365 pounds for the 130-hp Johnson 2-stroke it replaced.

The DF140 is considered a lean 4-stroke, with an excellent power-to-weight ratio. Even so, Herum knew the stern would sit too low in the water without some modifications. So he moved the batteries and live well forward. The batteries went inside the console — which was also new, but not necessary for the repower — and a live well was built into the console’s forward side. The new transom they built is 25 inches high, 5 inches more than the original.

When all was said and done, Herum had spent close to $10,000 on the repower, including the rebuilt transom, fuel tank replacement, deck modifications and engine mounting and rigging. That figure, however, does not include the Suzuki, which retails for $12,638.

Keep the boat you love

Repowering can be much easier and less expensive than it was for Herum. Ed Gallucci has repowered his 1999 Dakota, a 36-foot center console, twice in the last 10 years. He bought the boat with a pair of 250-hp 2-strokes (electronic fuel injection), then swapped them for Mercury OptiMax 225 2-strokes (direct fuel injection). But the boat was slightly underpowered with 450 horses, and Gallucci wanted the benefits of 4-stroke technology.

Repowering Jutras' Whaler involved adding two feet to the hull at the stern and a new transom.

“The OptiMaxes were great on gas, but I was tired of spending money on [2-stroke] oil,” says Gallucci, who is from Johnston, R.I.

With a pair of 300-hp Mercury Verado 4-strokes, Gallucci would be adding 270 pounds to the Dakota’s transom. “The weight was a concern,” he says. “But it turned out all right. With three people in the stern and full fuel, some water does come through the scuppers. But it’s very little and not a problem.”

And the benefits of the Verados certainly outweigh this small issue, he says. Gallucci says he has increased his cruising speed from around 35 mph to 40 mph, the power-assist steering makes driving the boat a pleasure, and the Verados are quieter than the OptiMax engines. Plus, he likes engines with an active warranty. Mercury backs the Verados with a three-year factory warranty.

Four-strokes aren’t always the answer. Paul Jutras of Jamestown, R.I., repowered with a 200-hp Evinrude E-TEC, Bombardier’s version of the direct-fuel-injected 2-stroke. Jutras has always run Evinrudes, and he was worried about the weight of a 4-stroke. Repowering his 22-foot 1980 Boston Whaler Outrage was part of a major project that involved adding 2 feet to the hull at the stern and a new transom.

New boats can be very expensive, says Jutras, and he wanted to keep his Whaler. “I knew its exact shortcomings, and I knew what I had to do to make it better for me,” he says.

Jutras does a specific type of fishing called “back trolling” along the rocky Rhode Island coast. The repower made sense because Jutras didn’t want to have to worry about bouncing a new boat off the rocks, he says.

The Whaler needed substantial work. Too much water was coming over the low, cut-out transom, says Jutras. With 2 more feet of hull length and a full transom, the boat would gain buoyancy aft, less water would enter the cockpit when he fished, and there would be room to add a live well.

Jutras, who owns a woodworking business, did all the work himself, putting in 350 hours. As it turns out, the rebuilt Whaler could probably handle the extra weight of a 4-stroke, but Jutras is perfectly happy with the Evinrude, having run it 300 hours with no problems.

Like Jutras, Skip Stritzinger chose to repower in the interest of fishing. A recent change from a 275- to a 300-hp Mercury Verado gave him about 15 percent better fuel efficiency, allowing him to run his Contender 25 at 30 knots with the engine set at 4,800 rpm. He had to push the 275-hp Verado to 5,000 rpm to achieve the same speed.

Stritzinger, who has repowered five times in the last 10 years, runs through a lengthy checklist to ensure a repower makes sense. “My decisions are based on 10 to 12 different criteria that cover areas like weight, [engine] noise, maintenance, acceleration and reliability.”

Stritzinger also considers whether to repower with a single engine or twins. There are pluses and minuses with each. For instance, a single-engine installation costs half as much, as does the maintenance. However, twins provide redundancy and get-home power if one engine fails. In addition, twin engines don’t have to work as hard as a single to push the boat to a cruise speed. Therefore, twins might outlast a single.

Pros and cons also exist when comparing 2- and 4-stroke technology, says Stritzinger. “The next generation of 4-strokes is better than they used to be out of the hole,” he says. “But they’re never going to have the punch of a 2-cycle.”

Boatbuilders adapt

Nevertheless, the popularity of 4-strokes continues to grow, with boats designed specifically for that power. Southport Boat Works of Leland, N.C., is one such boatbuilder. “We don’t even have a place for an oil tank,” says Frank Longino, a managing partner with Southport, referring to a 2-stroke’s oil reservoir.

The boats are built with significant buoyancy aft to accommodate 4-strokes, and the design allows the boat to accelerate out of the hole quickly and plane at a low speed, says Longino. “Four-strokes have a bad rep for low-end torque, but those older hulls weren’t designed for 4-strokes,” he says. “They were pushing the hulls up instead of forward.”

As a cost-saving measure, Al Herum had a crew of high school tech students rig and install the SeaCraft's new Suzuki DF140, which replaced the 130-hp Yamaha the boat came with.

Around six years ago, Contender raised the deck of its 31 center console 2 inches to compensate for the extra weight of twin 225-hp Yamaha 4-strokes. Its 2002 and 2003 model year 31s will allow some water into the cockpit through the scuppers when there are three or four people aft with a full live well, according to Contender national sales manager Bill Cordes. “It’s not unsafe; it just doesn’t self-bail as well,” says Cordes.

The introduction of the first 350-hp 4-stroke — the Yamaha F350 — prompted alterations to Pursuit’s C 34 center console, according to Matt Colbert, Pursuit director of engineering and product development. The builder beefed up the transom thickness from 2-1/2 inches to 4 inches and added a knee-shaped fiberglass support along the centerline to strengthen it. Without these modifications, the transom would not fail, but the gelcoat would crack because of the bending loads induced by the 804-pound V-8 4-strokes, says Colbert.

Standard power for C 340s built prior to 2008 is twin 250-hp Yamahas, V-6 engines that weigh in at 604 pounds each. The bottom line is that C 340s built prior to 2008 cannot be repowered with F350s unless the owner wants to risk stress cracks and structural failure, says Colbert.

There are certainly pros and cons to repowering, but if you do your homework you can determine whether it’s the right move for you. “My son is pleased, and I’m pleased with the boat,” says Herum, who repowered the SeaCraft. “I’m sending him out in a boat I’m confident is safe.”

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These articles originally appeared in the April 2009 issue.