Last reviewed: 2026-05-24 > Quick answer: Mercury no longer builds recreational 2-stroke outboards, so a 2-stroke repower today means a modern Mercury FourStroke. You gain quieter running, a cleaner idle, and 25 to 40 percent better fuel economy at cruise. You also add 15 to...
Last reviewed: 2026-05-24
Quick answer: Mercury no longer builds recreational 2-stroke outboards, so a 2-stroke repower today means a modern Mercury FourStroke. You gain quieter running, a cleaner idle, and 25 to 40 percent better fuel economy at cruise. You also add 15 to 25 kg, so transom, trim, and rigging need a look. Expect $11,000 to $24,000 CAD installed for a typical repower. Build a quote at mercuryrepower.ca.
Your old 2-stroke still starts. That is exactly what makes this a hard call. It fires on the second pull, it gets the boat on plane, and a new FourStroke is real money out of pocket. So the honest question is not whether a 4-stroke is better. Everyone knows it is. The question is what changes on your boat the day you make the swap, and whether the math fits the way you actually use the water.
We have pulled tired 2-strokes off Rice Lake transoms for decades. Some of those repowers were overdue. A few should have waited a season. Here is the straight version: what gets better, what gets worse, and what it costs in Canadian dollars.
What is the difference between a 2-stroke and 4-stroke outboard?
A 2-stroke fires the spark plug on every turn of the crankshaft. Power on every stroke. That makes it light, simple, and strong for its weight. The price of that simplicity is that it burns oil right along with the fuel, so it runs louder, dirtier, and thirstier.
A 4-stroke fires every second turn. It keeps its oil separate, in a sump or oil-injected, so it burns clean, idles smooth, and sips fuel by comparison. The trade is weight and a few more moving parts: valves, a camshaft, a timing chain.
For a repower today, Mercury has already settled most of the debate. The OptiMax had its run, but the current lineup is FourStroke and Pro XS, both four-stroke, plus the electric Avator. Repower now and you are going FourStroke. The real decisions are downstream: weight, rigging, and prop.
How does a FourStroke compare to the 2-stroke I am replacing?
Here is a modern 90 HP FourStroke against the 90 HP 2-stroke most Ontario customers are pulling off.
| Spec |
Older 90 HP 2-stroke |
Mercury 90 HP FourStroke |
| Dry weight |
~140 to 145 kg |
~163 kg (about 359 lb) |
| Idle |
Lopey, rough |
Smooth, quiet |
| Fuel burn at cruise |
~28 to 32 L/h |
~17 to 22 L/h |
| Oil |
Pre-mix or VRO injection |
Sump or oil injection |
| Noise at idle |
Loud |
Notably quieter |
| Emissions |
High, smoky |
Virtually none |
| Cold start |
Cranky |
Reliable |
| Top speed (same hull) |
Reference |
Within 1 to 2 mph |
| Hole shot |
Slightly quicker |
Slightly slower, more low-end torque |
| Maintenance |
Annual service plus plugs |
Annual service, longer intervals |
Three wins land the first morning you run it: the idle, the fuel gauge, and the quiet. The one real compromise is weight, and that is the next section, because it is the part people skip.
Does the weight difference cause any problems?
It can, and the boats that get this wrong are the ones where nobody asked the question. A FourStroke adds 15 to 25 kg at the very back of the boat. That changes how she sits at rest, how she trims at speed, and how hard the transom works. A vintage 90 HP 2-stroke runs about 140 kg, near 310 lb. A modern 90 HP FourStroke is closer to 163 kg, about 359 lb. On an 18-foot hull, that extra 50 pounds disappears. On a tight 15-footer, it can settle the stern far enough that water creeps toward the splash well.
Three things we check before any 2-stroke to 4-stroke repower:
Transom first. A boat 25 years and up can hide soft, wet core behind a skin that still looks fine. A heavier motor on a punky transom is a problem you do not want to meet on the water. We sound every transom before we install. If it needs repair, you hear it straight. If it is past saving, we say that too, even when the honest answer is a different boat.
Waterline second. A heavier motor drops the stern at rest. We check it against the scuppers and splash well so the new engine does not change how the boat sheds water.
Prop third. A FourStroke makes its torque differently than the 2-stroke did, so the prop that was right before is often wrong now. We re-prop most repowers and water-test on Rice Lake until the engine hits its rated RPM band wide open.
What rigging changes when you repower from 2-stroke to 4-stroke?
You cannot unbolt the old motor, hang the new one, and plug it into the same dashboard. The wiring, the throttle cables, the gauge protocols: all of it moved on. Most 2-stroke repowers roll in with mechanical controls two decades old, and a new motor deserves better than a worn shift box.
What we usually replace or add:
- Control box and cables (mechanical): $500 to $900
- Digital throttle and shift on 115-plus HP: $800 to $1,500
- Fuel line and primer bulb: $50 to $120
- Battery cables (modern motors pull more starting current): $80 to $200
- Tach and gauge cluster if going digital: $300 to $1,200
Budget $500 to $1,500 in rigging on top of the motor for a typical 2-stroke repower. That is already inside the installed prices we quote. Our what happens during a Mercury repower guide walks the full sequence, removal to water test.
How much does it cost to repower a 2-stroke to a Mercury 4-stroke?
Installed at Harris Boat Works on Rice Lake, ballpark CAD by motor HP:
- 25 HP FourStroke: $4,800 to $6,000
- 60 HP FourStroke: $9,500 to $12,000
- 90 HP FourStroke: $13,000 to $16,000
- 115 HP FourStroke: $16,000 to $19,000
- 150 HP FourStroke: $18,000 to $21,000
- 200 HP FourStroke or Pro XS: $21,000 to $28,000
The 75 to 115 HP class is the busy lane in Ontario, and most of those land between $13,000 and $19,000 before HST. Every full repower covers the motor, rigging, controls, propeller, a fuel-system inspection, hauling the old motor away, and a water test on Rice Lake before you pick it up. Pickup only, at Gores Landing. We do not ship motors and we do not deliver.
We take Mercury 2-stroke trade-ins, and we look at other brands case by case. Fill out the form on our trade-in value page and you get a CAD figure back by email inside one business day. Financing is available on approved credit. The full breakdown by motor class lives in our Mercury repower cost guide.
When should you repower instead of repairing the old 2-stroke again?
Three signals, usually. The repair quote crosses the line where you are paying to own the past instead of the future. The boat is still worth keeping even though the motor is not. Or the way you use the water has outgrown the engine: more people aboard, longer runs, fishing that wants a quieter ride.
Solid hull, boat still fits your life? Repower. You keep the boat you trust and replace the wear part. Tired hull, questionable transom, a layout that no longer matches your weekends? Then the honest conversation is about the boat, not just the motor. Either way, January through April is the planning window. Book the conversation before the spring calendar fills, because it does.
What we see at HBW
The happiest repower customers walked in expecting the trade, not just the upgrade. They wanted the quiet idle and the smaller fuel bill, and they already knew the transom would carry a little more weight. The repowers that disappoint are the ones where somebody skipped the transom check or never touched the prop, and a great motor ends up feeling wrong on a boat it should have transformed. That is why the transom inspection and the Rice Lake water test are not add-ons here. They are the job. The same crew that quotes your repower is the crew that rigs it and runs it off our dock.
Frequently Asked Questions
Can I still buy a new 2-stroke Mercury outboard?
Not in the recreational market. Mercury has shifted entirely to FourStroke and electric for new outboards. A repower replaces your old 2-stroke with a modern FourStroke.
Is a FourStroke heavier than the 2-stroke it replaces?
Yes. A 90 HP FourStroke weighs roughly 163 kg, about 359 lb, against about 140 to 145 kg for an older 90 HP 2-stroke. That 15 to 25 kg matters for transom strength and how the boat trims.
Will my boat still perform well with a FourStroke?
Almost always, yes. FourStrokes bring more low-end torque, cleaner planing, and far better fuel economy. On most hulls top speed lands within 1 to 2 mph of the old 2-stroke, and cruise is meaningfully more efficient.
Do I need new rigging when I repower from 2-stroke to 4-stroke?
Usually yes. Old mechanical controls and cables rarely match a modern motor. Plan for new controls, possibly digital, plus a fresh fuel line and wiring. Add $500 to $1,500 CAD for rigging.
Does Harris Boat Works take my old 2-stroke as trade-in?
We take Mercury 2-stroke trade-ins and look at other brands case by case for resale or wholesale. Fill out the trade-in form and we will email a CAD figure inside one business day.
How much does a 2-stroke to 4-stroke repower cost?
Installed at Harris Boat Works, a full repower runs $11,000 to $24,000 CAD for most jobs, depending on horsepower. That covers the motor, rigging, controls, propeller, fuel-system inspection, old-motor removal, and a water test on Rice Lake before pickup at Gores Landing.
Ready to plan your 2-stroke repower?
If your 2-stroke is on borrowed time, the winter planning window is where to start. Call us or build a quote and we will size the right FourStroke for your hull, transom and rigging check included.
Phone: 905-342-2153
Configurator: mercuryrepower.ca
Service: Harris Boat Works, a family marina in Gores Landing serving boaters since 1947
Phone: 905-342-2153
Address: 5369 Harris Boat Works Rd, Gores Landing, ON
Configurator: mercuryrepower.ca
Harris Boat Works, family-owned since 1947. A Mercury Platinum Dealer, selling Mercury since 1965.
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