Last reviewed: 2026-05-10 --- > Quick answer: Pontoons need torque and hole shot, not just top speed. For most 18 - 22 ft Ontario pontoons, Mercury 90 - 115 HP FourStroke with Command Thrust is the right answer (CT tops out at 115 HP; a 150 runs Mercury's big gearcase as...
Last reviewed: 2026-05-10
Quick answer: Pontoons need torque and hole shot, not just top speed. For most 18–22 ft Ontario pontoons, Mercury 90–115 HP FourStroke with Command Thrust is the right answer (CT tops out at 115 HP; a 150 runs Mercury's big gearcase as standard). For 18–20 ft two-log pontoons the 60 CT is often the hero pick. The gearcase matters as much as the horsepower number. Build an installed pontoon repower quote at mercuryrepower.ca.
Pontoon HP decision
How big is your pontoon and how do you load it?
Tube count and use case matter more than the HP number alone.
16 to 18 ft two-tube, cruising and light fishing
- ✓6 people maximum, no active water sports
- ✓Sheltered Kawartha bays, short runs
- ✓Fuel economy and quiet matter
- ✓You want the more affordable setup
90 HP Command Thrust FourStroke
20 to 22+ ft tritoon, full crew with water sports
- ✓8 to 10 passengers, tubing or skiing weekly
- ✓Open water on Rice Lake or larger Kawartha lakes
- ✓Fast hole shot with the boat loaded matters
- ✓Long-term hold, you want the right motor once
150 HP FourStroke (standard gearcase; CT tops out at 115. 200 HP on bigger tritoons.)
When in doubt:Command Thrust is the right gearcase on almost every pontoon in this HP range. The only real question is the HP number.
The gearcase is the part most people overlook
Customers shopping for a pontoon motor focus on the HP number. The gearcase is an afterthought, and that's the wrong order of priorities.
A 90 HP Command Thrust and a standard 90 HP look almost identical on a spec sheet. Same horsepower. Same motor family. But Command Thrust uses a larger gearcase, a larger prop, and a torque-tuned gear ratio that's built for heavy boats. On a pontoon, that means faster lift to cruise when you have six people aboard, better load-carrying, and a boat that feels like it has more motor than the number would suggest.
We default to Command Thrust on most pontoon repowers at HBW. Customers who push back on the small price difference, and then see the boat run with the right gearcase, get it immediately. For installed cost ranges on pontoon repowers in this HP band, see the boat repower guide.
What changes the right Mercury for your pontoon
Pontoon length and tube configuration. Two-tube pontoons under 20 ft have different needs than 22 ft tritoons. The hull matters.
Use case. Cruising and fishing without water sports is a very different ask than active tubing, skiing, or wakeboarding. Same boat, different right answer.
Passenger and gear loading. A 22-foot pontoon with eight people and a full cooler needs more motor than the same pontoon with two adults and a fishing rod.
Where you boat. Sheltered Kawartha bays vs. open water on a big lake vs. running the Trent-Severn system all change the practical HP minimum.
Capacity plate. The plate sets the legal ceiling. Pontoons typically rate 90 to 150 HP, or 115 to 200 HP, depending on size and tube configuration. We work within it.
Best Mercury for pontoons by use case
| Pontoon use case |
Practical Mercury range |
HBW note |
| 18–20 ft two-log, cruising and fishing |
60 HP Command Thrust (hero) or 90 HP CT |
Lighter two-log pontoons run great on the 60 CT. |
| 20–22 ft, family cottage use |
90–115 HP Command Thrust |
The sweet spot for Rice Lake pontoons. |
| 22–24 ft, active water sports |
115 HP Command Thrust or 150 HP FourStroke (standard gearcase) |
CT tops out at 115; above that, the 150 runs the big gearcase as standard. |
| Large tritoon or performance setup |
150 HP and up (standard gearcase) |
Verify hull rating, steering, and transom before quoting. |
18–20 ft two-log pontoon, cruising and fishing only
Best fit: 60 HP Command Thrust FourStroke. For lighter 18–20 ft two-log pontoons, the 60 CT is often the right call and our hero recommendation, see our Mercury 115 vs 150 HP honest dealer guide. Step up to a 90 HP Command Thrust for heavier loads or longer runs. Standard gearcase 90 also works, but Command Thrust handles the pontoon hull better.
18–20 ft pontoon, family use with occasional water sports
Best fit: 115 HP Command Thrust FourStroke. The step up from 90 to 115 CT is meaningful for water sports because hole shot with a loaded family aboard is much stronger. For occasional tubing with kids, 115 CT is the right call.
20–22 ft pontoon, active water sports
Best fit: 150 HP FourStroke (standard gearcase). Command Thrust tops out at 115 HP, so the 150-class recommendation is Mercury's big standard gearcase, which is what the 150 ships with anyway. Pulls skiers cleanly, handles wakeboarding loads, runs comfortably in chop. Above 150 HP on a traditional two-tube pontoon starts to return diminishing gains because the hull design itself limits top speed.
Tritoons (three-tube), 22–24 ft
Best fit: 150 HP and up (standard gearcase). The third tube changes the hydrodynamics and lets the boat reach higher speeds with adequate HP. For 22–24 ft tritoons with active water sports, 200 HP FourStroke (standard gearcase) is typical.
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Why Command Thrust makes the difference on pontoons
You can build a live CAD quote for your repower online at Mercury Repower Centre.
Pontoons are unique among recreational hulls:
- Blunt-fronted, the noses push water rather than slice it
- Heavy, aluminum tubes, fibreglass furniture, full hardware add up fast
- Wide, more drag than a similar-length runabout
- Slow to come up on cruise, the hull design fights the transition from displacement to cruise
Standard gearcases are built around runabout hydrodynamics. Command Thrust matches pontoon physics:
- The bigger gearcase nose handles heavier load without cavitation
- The larger prop pushes more water per revolution for better hole shot
- The torque-tuned ratio gets the boat up on cruise sooner at lower speeds
- The lower cruise speed lets pontoons run efficiently
The result: noticeably stronger hole shot when loaded, faster time to cruise, better load-handling for water sports. None of these come from extra HP, they come from the gearcase.
Common pontoon motor mistakes
1. Skipping Command Thrust to save money. The single most common pontoon repower mistake. Customer picks the standard 90 HP, and trades up to Command Thrust within two or three seasons. Pay once.
2. Buying too small for water sports. A 90 HP on a 20-foot pontoon used for tubing disappoints. Active water sports want 115 CT minimum; a 150 (standard gearcase) is preferred, since CT tops out at 115.
3. Buying too much for cruising only. A 200 HP on an 18-foot pontoon used for sunset cruises is overkill and extra fuel burn. The 90–115 CT range handles cruising elegantly.
4. Wrong prop on a Command Thrust gearcase. Command Thrust gearcases need Command Thrust props, the larger diameter and different geometry aren't compatible with standard props.
5. Forgetting about the trailer. Pontoon trailers on older setups are often the limiting asset. Check trailer condition before committing the repower budget.
Tritoon vs two-tube: when to step up
Customers sometimes ask whether to upgrade their two-tube pontoon to a tritoon during a repower. The honest answer: switching from two-tube to tritoon is a new pontoon purchase, not a repower project. The hull is the asset, you can't cost-effectively retrofit a third tube to most existing two-tube pontoons.
If your needs have shifted toward active water sports and your two-tube isn't keeping up, the conversation is really about whether to sell and buy a tritoon. We sell new Legend Boats and are happy to work through that decision with you.
Mercury Boost on a pontoon: when it actually helps
Mercury Boost is a software calibration that improves mid-range acceleration response by 5-21 percent on eligible motors. It does NOT add peak horsepower at WOT. On a pontoon, that distinction matters more than on most other hull types.
When Boost helps on a pontoon:
- You run a tritoon with a 200-300 HP V8 Pro XS and tow tubes or skiers regularly. Faster mid-range punch out of the hole is real, repeatable, and noticeable.
- Your existing motor is on Mercury's eligible serial range (2B529482 or later for the relevant V8 families).
- You already have enough peak HP for the boat loaded. Boost sharpens response, not top speed.
When Boost does NOT help on a pontoon:
- You run a standard two-tube pontoon with a 90 or 115 Command Thrust. CT is the right answer here. The 115 CT is not on the Boost eligibility list, and the gearcase plus prop pairing is already optimized for hole-shot on a standard pontoon.
- You spend 80 percent of your time at steady cruise. Boost is invisible at constant throttle.
- The underlying motor is undersized for the hull. Boost will not fix that. You need a bigger motor, not a calibration upgrade.
The honest pontoon-specific framing: For a typical two-tube pontoon in the Kawarthas, the right answer is a 90 or 115 Command Thrust FourStroke. For a tritoon or a pontoon used for serious watersports, a 200-300 HP V8 Pro XS with factory Boost (or the dealer-installed Boost calibration on an eligible serial) is the upgrade path. Boost is not a substitute for the right base motor.
For full Boost eligibility detail by motor family and serial range, see our Mercury Boost software upgrade eligibility guide.
Related posts
Ready to repower your pontoon?
Build a quote at mercuryrepower.ca. The system asks for your hull info and use case and recommends the right HP class and gearcase. Or call 905-342-2153, we rig pontoons every week and can give you the honest answer for your specific hull.
About the author
Jay Harris helps run Harris Boat Works, a third-generation family marina in Gores Landing on Rice Lake, established in 1947. HBW is a Mercury Marine Premier Dealer and Legend Boats dealer serving Rice Lake, the Kawarthas, and Ontario boaters who want straight answers before spending real money. Read Jay's full bio.
FAQ
What's the best Mercury for an 18-foot pontoon?
For cruising and fishing without water sports, 90 HP Command Thrust FourStroke. For occasional water sports with the family, step up to 115 HP Command Thrust.
What's the best Mercury for a 20-foot pontoon?
Cruising and fishing: 115 HP Command Thrust. Active family use with tubing or skiing: 150 HP FourStroke (standard gearcase; CT tops out at 115). Above 150 HP on a two-tube pontoon starts to hit diminishing returns.
Do I need Mercury Command Thrust on a pontoon?
For pontoons 18 ft and up, yes in most cases. Command Thrust gives meaningful hole shot, load-handling, and pulling power that the standard gearcase can't match on pontoons. The cost premium is worth it.
Can I use my pontoon for water sports?
Yes, with the right HP. Tubing: 115 HP CT or higher. Skiing: 115 HP CT minimum, step to a 150 (standard gearcase) if you want more. Wakeboarding: 150 HP or higher (standard gearcase; CT tops out at 115). Pontoons purpose-built for water sports (some tritoons) handle this best.
Should I get FourStroke or Pro XS for a pontoon?
FourStroke is almost always the right answer for pontoons. Pro XS is built for tournament fishing and performance applications, not the load-handling and cruising emphasis pontoons need.
What's the most popular Mercury for pontoons in Ontario?
The 115 ELPT Command Thrust FourStroke. Fits the most common pontoon (20 ft two-tube), the most common use case (family cruising with occasional water sports), and the most common capacity rating.
Ready to price it out? Build a live CAD quote for your repower online at the Mercury Repower Centre.
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