Retrofit your boat with a new outboard

Whether we like it or not, someday most of us will need to buy an outboard engine. Perhaps it’s for that great boat that we bought cheap but that didn’t come with a motor, or perhaps it’s when our existing outboard’s lacklustre performance, the difficulty in getting parts, or a major breakdown signals it’s time for the scrapyard. Problem is, there are so many different makes and models out there that it’s difficult to know where to begin when looking for a replacement.

Modern outboards—two- and four-stroke—have evolved significantly in the last decade, as a result of both advances in technology and stricter exhaust-emission standards. Today’s models use far less fuel, are much quieter, are considerably more reliable, and are much friendlier to the environment than older generations. They also have features never envisioned even a decade ago: electronic controls; high-tech digital engine monitors; improved get-home safety systems, which allow malfunctioning engines to operate for short periods of time under reduced power; and, new in 2013, joystick steering.  

The first step in replacing an outboard is to assess the condition of the boat. “If you put on a new motor, you’re spending upwards of $10,000 to $15,000,” says Jennifer Picken, president of Walsten Marine in Kinmount, Ont., “so we want to make sure the boat is sound before we go any further.” Next, check out the existing engine, if the boat has one, for horsepower, weight, and shaft length.

Factor 1: Horsepower
Ratings have increased over the years, so the horsepower of your new engine may be different than that of your old one. This is because the method for measuring horsepower has changed. Gary Coleman, national service manager for Mercury Marine Canada, based in Milton, Ont., points out that in outboards built before the late 1980s, horsepower was measured 
at the powerhead. These days, it’s measured at the prop shaft. The inherent loss of horsepower between the powerhead and the prop shaft means that, for example, a new 40 hp outboard 
is roughly equivalent to an older 50 hp model. Look for the vessel’s capacity plate/label, located somewhere on the hull. Exceeding the maximum horsepower rating will void any warranty on the boat and it may be difficult, if not impossible, to get insurance.

If the boat is sound but its flotation has become waterlogged, or if it is carrying a lot of gear, the added weight can result in slow acceleration and sluggish performance, signalling the need for a larger outboard, if capacity allows. How you use your boat makes a difference too: Ski and wakeboard boats need the most horsepower, while pontoon and fishing boats can get away with less. 
A boat being used in a calm waterway won’t need as much horsepower as one travelling long distances offshore.

Factor 2: Weight
This can be a significant factor in a 
new engine purchase since four-strokes weigh more than two-stroke engines. 
“If the boat has a 90 hp two-stroke and you’re going to replace that with a 90 hp four-stroke, you have to make sure that there is not going to be too much weight on the back of the boat,” Picken says. Extra weight can make the boat diffi-cult to get up on a plane, says J.F. Rioux, 
outboard product manager for Yamaha Motor Canada, and can cause it to sit too low in the water, which will affect cockpit drainage and potentially allow water ingress over the transom. If the boat is already sitting on its lines with the old outboard, be cautious about installing a heavier engine.

Factor 3: Shaft length
This should be the same on the new 
outboard as on the old one; however, 
not all outboards are produced in multiple shaft lengths, and this may limit your choice of brands. For optimal performance, an outboard’s horizontal cavitation plate (just above the prop) must 
be level with the bottom of the transom. Matt Maynard, of Hastings Marine in Norwood, Ont., explains that the cor-
rect shaft length can be found by meas-uring the distance from the top of the transom (or outboard mounting plate) straight down to the very bottom of 
the transom—the deepest part.  

Factor 4: Rigging, gauges
Most new outboards no longer come packaged with controls (the shifter-throttle, mechanical cables, and wiring harness) or propellers. Depending on 
the brand and the age of the old controls, an adapter kit may be available from the engine manufacturer or an aftermarket parts supplier. These kits allow a new outboard to work with old controls, as long as they are the same brand. While there are potential savings in buying an adapter kit instead of all new controls—which will run at least a few hundred dollars—from a safety and security point of view, it makes sense to replace the controls at the same time as the engine, even if peace of mind costs a few dollars more.

Marine dealers can no longer legally reconnect the old pulley-clothesline steering systems, so you will definitely have to replace one of those with a more reliable cable system. Hydraulic steering systems are available for engines 
of more than about 150 hp and start at around $1,500. Figure on at least twice that for power steering.

Digital engine-monitoring gauges that mount on the console are now available for many 30-plus horsepower outboards, starting at $500. Their multifunction LED screens provide a mind-boggling array 
of valuable data. In addition to what normally appears on stand-alone analog gauges, such as oil pressure, rpm, and temperature, you’ll get everything from fuel consumption and engine diaries to engine diagnostics. Electronic controls, for engines of more than about 200 hp, allow for smoother shifting and less maintenance and are often easier to install than mechanical controls.

The cost of installation also depends on accessibility. As Gary Campbell of Campbell’s Landing in Gravenhurst puts it: “There are many different shapes, models, and styles of boats, and some installations require taking the boat apart while others are simple.” According to Matt Maynard, customers should expect to pay about $400 for a standard install, which includes mounting the engine properly, running the controls and cables, putting in the control box, and setting up the motor to meet warranty requirements (only the dealer can do the latter because they have the specialized computer equipment needed). It’s also a good idea to ask your dealer to take the boat out for a spin to make sure that the controls are properly tweaked and the engine is fitted with the appropriate propeller.

You may find a better price on an outboard by shopping around; however, there is an advantage to buying from your local dealer, someone who will make sure your warranty is valid 
and reward your loyalty by providing prompt, personal service throughout the life of the outboard. There’s also a good chance that you can save money by negotiating a package price that includes the engine, installation, and on-water testing.