ePropulsion Spirit 2 VS Mercury 5HP: Which outboard is cheaper over time?

The price gap between an electric outboard and a gas outboard gets a lot of attention. What doesn't get enough attention is what happens to that gap over time.

The ePropulsion Spirit 2 costs $4,199. A Mercury 5hp runs $1,735. That's a $2,464 difference at the register, and we're not going to pretend that isn't significant. It is.

But if you're buying a motor you plan to use for the next decade, the purchase price is only the beginning of the conversation. Fuel, winterization, impeller replacements, scheduled service — it all adds up on the gas side in ways that are easy to underestimate when you're standing in a showroom.

We ran the full numbers over 12 years. Here's what we found.

The Two Motors

ePropulsion Spirit 2 ($4,199 with battery) — 2kW continuous / 3kW boost mode electric outboard with a 1,539Wh removable lithium battery. Equivalent to a 5hp gas motor in continuous power, with a 6hp burst mode for getting light hulls up on plane. Weighs about 50 lbs total (motor + battery + bracket) but once broken into its three parts, you're never handling more than 23 lbs at once. No oil, no winterization, no impeller, no pull start. The ePropulsion Spirit 2 charges from a standard wall outlet in about 8 hours, or 2 hours with the fast charger. The battery is user-replaceable — a key advantage over some competitors.

Mercury 5hp ($1,735) — Four-stroke, water-cooled gas outboard. A proven, widely available motor with a strong dealer network. Heavier than the Spirit 2 at 55 lbs for the motor alone, before you add fuel. And you have to handle all that weight at once. Has a carburetor, cooling system, impeller, and all the maintenance that comes with them.

These two motors compete in the same category — portable outboards for small boats, tenders, inflatables, and auxiliary sailing applications. They're genuinely matched in power output, which makes it a useful comparison.

What We're Counting

We modeled 12 years of real ownership costs, line by line. Here are the assumptions we used.

Shared assumptions:

• 25 hours of use per year at full throttle
• National average gas price: $3.10/gallon (2025 EIA average)
• National average electricity rate: $0.18/kWh (2026 EIA data)

Mercury 5hp annual and periodic costs:

• Fuel: ~$39/year (25 hrs × 0.5 GPH × $3.10)
• Winterization: $175/year — slightly higher than a smaller air-cooled motor because the Mercury 5hp has a water-cooled system with more to flush and prepare for storage
• Miscellaneous repairs: $75/year — fuel lines, props, tune-ups, things that come up on a gas engine that lives outside all season. Conservative.
• Scheduled service (oil, spark plugs, gear oil, shop labor): $250 every 4 years
• Impeller replacement: $125 every 4 years — the Mercury 5hp is water-cooled, so the impeller needs periodic replacement. At 25 hrs/yr we've modeled this every 4 years on a calendar basis, which is realistic for seasonal use.

ePropulsion Spirit 2 periodic costs:

• Electricity: ~$9/year (1,539Wh per charge × ~33 charges/year × $0.18)
• Maintenance: $0/year for oil, plugs, winterization, or impellers
• Anode replacement: $50 at years 5 and 10 — anodes protect the lower unit from corrosion and need periodic replacement, especially in saltwater
• Prop replacement: $67 at years 5 and 12 — props get dinged. We've modeled two replacements over 12 years.
• Battery replacement at year 7: $1,575 — unlike some electric outboards, the Spirit 2's battery is fully user-replaceable. You're buying a new battery, not a whole new motor. We've modeled this conservatively at year 7; under light seasonal use with proper storage the battery may well last longer.

The Numbers

This comparison tells a different story than you might expect. Unlike a smaller electric motor with a lower purchase price, the Spirit 2 starts out significantly more expensive — and the Mercury actually holds the cost advantage through most of the ownership period. The lines cross somewhere around year 10 or 11, depending on your gas price and usage.

By year 12, the Spirit 2 comes out ahead by a relatively modest margin under national average assumptions. The real question isn't just who wins at year 12 — it's what happens after that. The Spirit 2's running costs are so low that the gap widens significantly the longer you keep it. If you're a boater who holds onto equipment, the electric math keeps improving. If you tend to sell and upgrade every five or six years, gas may still be the more economical choice.

The Honest Caveats

We put a lot of thought into making these numbers fair. Here's what you should know before drawing conclusions.

The Spirit 2's battery replacement is a big variable. We modeled it at year 7, which is conservative. The Spirit 2 battery is rated for 1,000 cycles at 80% state of health. At 25 hours per year with roughly one full charge per use, you're looking at about 33 charge cycles annually — which puts you at 1,000 cycles around year 30, not year 7. The actual limiting factor is calendar aging, not cycle count. A battery stored properly at 50-60% charge over winter could realistically last 10 or more years. If the battery makes it to year 10, the Spirit 2's 12-year cost advantage grows considerably.

Gas prices matter more here than in our smaller motor comparison. At 0.5 GPH, the Mercury burns more than twice as much fuel as the Honda BF2.3 we covered in our last post. That means gas price swings have a bigger impact on the total cost picture. Use the interactive calculator below to plug in your local gas price. At $3.10 per gallon, our gas price is very conservative, especially if you're buying gas on the water.

The ePropulsion Spirit 2 has a big upfront cost that is genuinely hard to overcome in the short term. We're not going to spin this differently than it is. If you sell your boat in five years, the Mercury probably cost you less. The Spirit 2's value proposition is strongest for boaters with a longer ownership horizon.

The service network for electric outboards is still smaller. If something goes wrong with a Mercury, you can find a mechanic almost anywhere. ePropulsion's dealer network is growing, but it's not at that level yet. For most boaters this isn't a practical concern since electric outboards have very few failure points — but it's worth knowing.

What This Tells You

The Spirit 2 is not the easy financial win that a smaller electric motor can be. The purchase price is real, and it takes time to recover. But the cost trajectory is unambiguous — the longer you own it, the better the math gets.

At 12 years under national average assumptions, the Spirit 2 comes out ahead. And it's worth noting that 25 hours per year is a conservative estimate — plenty of boaters use a motor like this significantly more. The more you use it, the faster the electric advantage compounds. Every additional hour on the water is fuel you didn't buy, a trip to the marina you didn't make, and $0 in running costs on the electric side.

But here's what the spreadsheet doesn't capture.

You're not dealing with gas anymore. No jerry can. No spills. No smell on your hands, your boat, or your gear. No standing at a pump trying to figure out if you have enough for the season.

Push button start, every time. No choke, no priming, no yanking a pull cord six times in front of your family. You push a button and you go. That sounds small until you've dealt with a gas outboard that won't start on a Saturday morning.

No marina runs for maintenance. Every year with a gas outboard, you're scheduling a winterization appointment, dropping the motor off, waiting for it, picking it up. With the Spirit 2, that entire category of your life disappears. Rinse it with fresh water after saltwater use, store the battery at 50-60% charge over winter, and you're done. That's real time back in your life.

It's better for the water you're on. No fuel in the water, no exhaust fumes, no emissions. If you're fishing, sailing, or just cruising a quiet harbor, that matters — both for the environment and for the experience.

Less weight to handle. The Mercury 5HP is only 5 pounds heavier than the ePropulsion Spirit 2 (55 lbs vs 50 lbs), but that doesn't tell the entire story. When you go to pick up that Mercury, you have to handle all 55 lbs all at once. The Spirit 2 breaks into three parts: motor, battery, and bracket. The shaft and battery each weigh about 23 lbs and the bracket is about 6. You're not picking up 50 lbs, you're only lifting 23!

The cost analysis we've done here is honest, and the answer isn't a blowout in either direction. What it shows is that the Spirit 2 is financially competitive over a realistic ownership period — and that's before you put any value on never winterizing a motor again.

Questions?

If you're weighing the Spirit 2 against a gas motor and want to talk through whether it makes sense for your specific boat and use case, give us a call at 631-204-8188 or email luke@emoelectric.co. We'll give you a straight answer, even if it's not the one you were hoping for.

Methodology: Cost projections assume 25 hours of use per year at full throttle. Gas priced at $3.10/gallon (2025 EIA national average). Electricity priced at $0.18/kWh (2026 EIA national average). Mercury 5hp costs include $175/year winterization, $75/year miscellaneous repairs, and combined service + impeller replacement of $375 every 4 years. ePropulsion Spirit 2 costs include electricity at approximately $9/year, anode replacements of $50 at years 5 and 10, prop replacements of $67 at years 5 and 12, and a battery replacement of $1,575 at year 7. Prices are not inflation-adjusted.