New Fuel-Sipper Or Old Gas-Guzzler?
Published: Monday, March 23, 2020
By: John Tiger
As time and technology move further along, boaters with older engines are faced with repair-or-replace decisions when their older outboards need repair, become less reliable, or stop working altogether. What to do? New engines are often prohibitively expensive. Even a mid-sized outboard (90-140hp) will easily top $10 large rigged and out the door. That’s a lot of coin for most anyone, especially when you don’t have it; when repowering a 20+ year old boat that’s otherwise perfectly seaworthy, it’s a gut-check.
Buying a new outboard today is a very large commitment, especially for those who might only use their boat just a few times per summer. Repairing what you have or buying a nice rebuilt engine can be a reasonable alternative. However, there’s more to it than the initial cash outlay. Are newer outboards radically improved compared to twenty years ago? Newer four-stroke and direct-injected two-stroke outboards have much more sophisticated fuel management systems, and like today’s cars, pollute significantly less than those made even ten years ago. In the end, the bottom line is: are they worth their price tag, especially for a “toy” that likely gets used less than one total month per year?
Less Emissions Or More MPG?
The popular take on newer outboards is that they’re less damaging to the environment, which is absolutely true. Direct injection two-strokes and fuel-injected four-strokes indeed disperse significantly less in the way of emissions into the water and atmosphere than their older carbureted and EFI ancestor two-strokes did—no question. Like older outboards, new DFI engines use an oil-burning two-stroke design, but they inject the fuel/air and oil charge directly into the cylinder with such high precision and timing that the result is a dramatic drop in emissions, and an equally dramatic rise in fuel economy, as well as less oil use. Four stroke outboards, of course, do not use any oil.
What does all this mean? Simply, today’s four-stroke and DFI two-stroke outboards burn a lot less fuel than their older predecessors. A lot of that is due to the technology involved; this means that more of the fuel/air charge is actually burned than dumped straight into the water and air than was with the older engines. But a lot of it is also due to the fact that, put simply, since the newer technologies allow for much more efficient fuel burn, then less fuel is actually burned! To the boater, this means less gallons per hour burned, more miles per gallon achieved, more money in your wallet, and less spent at the fuel dock.
How much more? Here are some 
general statistics, proven over time via accurate testing from both the engine manufacturers and independent boating publications:
New engines burn between 35% and 50% less fuel than their older carbureted brothers. The difference is higher at idle and midrange speeds, of course; at full throttle, the difference is more like 10-15%.
The reduction in emissions pollution is an equal amount to the fuel burn delta.
Thanks to the computerized fuel flow and ignition/electrical systems, the newer engines are very comparable to newer cars in ease of starting and running quality. Older carbureted engines had to be choked/primed to start, and would surround you in a cloud of blue smoke until they warmed up. Newer engines start without any special procedures, and there’s virtually no smoke at startup and while running.
Cost Differences
As mentioned, the cost for this efficiency and ease of operation is high. A new 115, for example, will cost between $8000 and $11,000 depending on the dealer’s price, rigging, extras, and setup. To rebuild an older engine of similar size might cost $3000-$4000. That’s a big price delta, so consider carefully. The cost difference will buy a lot of gas. What it won’t buy, of course, is peace of mind. Newer engines come with long warranties; depending on the manufacturer’s promotion, a new engine warranty can be three years to even 10 years! In addition, a newer engine will always be welcomed for service at the local dealer. Older engines, not so much. Most dealers have an age limit on engines they’ll service. Typically, it ranges from ten to twenty years old. Beyond that, you’ll have to find an older engine specialist.
What’s the Right Answer?
There’s a lot to consider, a lot at stake. Money, family time, environmental consciousness; these are all valid concerns. Finally, consider the “new engine” factor—that is, there’s nothing quite like a new engine. It starts easier, runs nicer, idles better, and shifts more smoothly. For many, the “Wow, its new” factor is enough to head down to the dealer to check out the new outboards.
This article first appeared in the Spring Issue (Mar/Apr) 2020 of Great Lakes Scuttlebutt magazine.
tags: Engines, Retrofitting
