Mercury 9.9 HP Outboard: 11 Best EFI, Command Thrust & ProKicker Models (2026)

A Mercury 9.9 hp outboard is a small two-cylinder four-stroke, and it comes in three main versions. The standard model is for tenders, jon boats and small skiffs. The Command Thrust version adds a bigger gearcase and prop to push heavier boats. The ProKicker is built as a trolling and back-up motor for larger fishing boats.

In June 2024 Mercury moved the 9.9 from a carburettor to electronic fuel injection (EFI). It also claimed up to 27% better fuel economy than the old carburetted models (Boating Industry Canada on the 2024 Mercury EFI launch). We stock 11 versions of the Mercury 9.9 hp outboard, from $2,865 to $3,745, and ship them worldwide.

This guide covers the specs, the differences between the versions, how to read the model codes, and which one fits your boat. If you already know what you want, go straight to the full price list or the Mercury 9.9 HP category.

Why the Mercury 9.9 HP Outboard Is So Popular

The odd number isn’t an accident. In several places, 10 horsepower is a legal line, so engines rated just under it are useful.

• Canada: Transport Canada says any pleasure craft powered by 10 horsepower or more needs a licence (Transport Canada pleasure craft licensing). A 9.9 sits under that line.
• Some US lakes: On certain Missouri Department of Conservation lakes, outboards over 10 horsepower must run at slow, no-wake speed (Missouri Department of Conservation boat and motor rules). Many other lakes and reservoirs around the world have their own horsepower caps.

Rules change and vary by country, region and even by lake, so always check what applies where you boat. The point is that a Mercury 9.9 hp outboard often gives you the most power you can run without extra paperwork or restrictions. It’s also the classic size for a kicker motor on a bigger fishing boat.

What’s Inside a Mercury 9.9 HP Outboard

The current Mercury 9.9 hp outboard is a 209 cc inline two-cylinder four-stroke with EFI. The main points, from Mercury’s 2024 launch coverage and current dealer spec listings:

• Fuel injection. Mercury’s launch release said the EFI 8 and 9.9 use up to 27% less fuel than the earlier carburetted models. That’s Mercury’s own figure.
• No cranking battery needed on manual-start models. Mercury’s Jim Hergert explained that pulling the cord “automatically charges the entire electrical system to enable ignition.” So a manual-start Mercury 9.9 hp outboard can run with no battery on board.
• Lower maintenance. BoatNews reported no oil filter and a maintenance-free camshaft, plus a freshwater flush fitting for a standard garden hose (BoatNews on the Mercury EFI 8 and 9.9).
• Charging. A 12-volt, 12-amp (145-watt) alternator, according to Defender’s spec listing (Defender: Mercury 9.9 tiller specifications).

Mercury’s own product page describes “battery-free electronic fuel injection (EFI) technology,” forward-reverse shifting in the tiller grip, a ratcheting tilt bracket, and “saltwater-safe components and corrosion-preventative technologies” (Mercury 9.9hp EFI Command Thrust product page).

Mercury 9.9 HP Outboard Specifications

Here are the published numbers for each Mercury 9.9 hp outboard version. We’ve listed the source for each column, because different versions and model years differ.

Sources for the table: Defender 9.9 tiller listing, Defender 9.9 Command Thrust ProKicker listing and Mercury 9.9 and 15hp EFI ProKicker spec sheet.

Why two ProKicker columns? Mercury’s older ProKicker spec sheet lists a 333 cc engine at 122 lb. Current dealer listings for the new EFI ProKicker show the 209 cc engine at 115 lb. Both are real Mercury engines from different generations. If the exact engine matters to you, ask us to confirm the model year and engine before you order. We’d rather you know exactly what’s in the crate.

The Three Versions of the Mercury 9.9 HP Outboard

Standard 9.9: light and simple

This is the everyday Mercury 9.9 hp outboard. It’s the lightest version, at 88 to 97 lb dry depending on starting and shaft. It’s the one for tenders, inflatables, small aluminium boats, canoes on a side bracket and small sailboats. You can pick manual or electric start and a 15, 20 or 25-inch shaft.

The cheapest way in is the Mercury 9.9MH at $2,865, a 15-inch manual-start tiller. Most small aluminium boats take the 20-inch 9.9MLH at $2,885. If you want push-button starting, the 9.9ELH is $3,230.

Command Thrust: more push for heavy boats

Command Thrust (CT in the model code) is Mercury’s name for a larger, heavy-duty gearcase that swings a bigger propeller. It doesn’t add horsepower. What it changes is how well the engine pushes a heavy or wide boat at low and mid speeds. A Command Thrust Mercury 9.9 hp outboard makes sense on small pontoons, loaded workboats, heavy sailboats and any boat that feels sluggish with a standard prop.

Our Command Thrust range starts with the 9.9MLH-CT at $3,030. For comparison, Mercury’s US website currently lists the 9.9hp EFI Command Thrust tiller “From $3,335.”

ProKicker: the trolling and back-up motor

The ProKicker is a Mercury 9.9 hp outboard set up to sit beside a bigger main engine on a fishing boat. Anglers use it to troll slowly and precisely for walleye, salmon and other species, and as a way home if the main engine fails. Mercury’s 2024 launch material describes:

• A high-thrust four-blade propeller for precise trolling speeds.
• A heavy-duty Command Thrust gearcase.
• Standard power tilt. As Hergert put it: “You just push the button and it effortlessly raises the motor.”

The older ProKicker spec sheet makes the same points: a “high-thrust four-blade propeller for better troll control” and “standard power tilt.”

We stock two: the 9.9ELHPT-CT-PK (20-inch shaft, $3,665) and the 9.9EXLHPT-CT-PK (25-inch shaft, $3,745). Most kicker brackets on big fishing boats need the 25-inch version, but measure first.

How to Read Mercury 9.9 HP Outboard Model Codes

Every letter in a Mercury 9.9 hp outboard model name means something. Once you know them, you can read any Mercury 9.9 hp outboard listing at a glance:

• M = manual (pull-cord) start.
• E = electric start.
• No shaft letter = 15-inch short shaft.
• L = 20-inch long shaft.
• XL = 25-inch extra-long shaft.
• H = tiller handle.
• PT = power tilt.
• CT = Command Thrust gearcase.
• PK = ProKicker.

So “9.9EXLHPT-CT-PK” means electric start, 25-inch shaft, tiller, power tilt, Command Thrust, ProKicker. And “9.9MLH” means manual start, 20-inch shaft, tiller. That’s all there is to it.

Every Mercury 9.9 HP Outboard We Sell

All engines below are new. Prices were correct when we wrote this guide; the product page always shows the current price.

Standard 9.9

Command Thrust 9.9

ProKicker 9.9

A few patterns in those prices. Electric start adds about $350 over manual on the standard models. Command Thrust adds roughly $70 to $165 over the standard version with the same start and shaft. The ProKicker package adds another $365 or so over a Command Thrust electric-start model. That gets you power tilt and the kicker set-up.

Which Mercury 9.9 HP Outboard Fits Your Boat?

Inflatable tenders and RIBs

Go light. A standard 15-inch Mercury 9.9 hp outboard like the 9.9MH is the usual pick for a 3 to 4-metre RIB. Manual start keeps the weight down, and you don’t need a battery. Check the tender’s maximum horsepower plate first, because some small inflatables are rated below 10 HP. Our guides to inflatable boat motors and outboard motors for dinghies cover fitting and handling.

Jon boats and small aluminium skiffs

Most 12 to 14-foot aluminium boats have a 20-inch transom, which points to the 9.9MLH or the electric-start 9.9ELH. If the boat is wide, heavily loaded or used for hauling gear, the Command Thrust 9.9MLH-CT will feel noticeably stronger. See our outboard motors for jon boats guide.

Small sailboats

A sailboat needs push at low speed and a prop that stays in the water when the stern lifts. A 25-inch Command Thrust Mercury 9.9 hp outboard, such as the 9.9MXLH-CT or electric-start 9.9EXLH-CT, is a good fit for a larger trailer sailer. Our page on outboard motors for sailboats covers mounting and prop choice.

Small pontoons

Pontoons are heavy for their length and push a lot of water. A Command Thrust model is the one to pick if you’re powering a small two-tube pontoon on a quiet lake. If your pontoon is big or you want real speed, look at more power. Our outboard motors for pontoons guide can help.

Kicker motor on a larger fishing boat

This is ProKicker territory. The high-thrust prop holds slow trolling speeds better than a big main engine can, and the power tilt lifts it clear when you run on the main engine. Read our guide to the best outboard motors for trolling, and if you’re running a big main engine like a Mercury 250 hp outboard, a ProKicker makes a sensible partner.

Manual Start or Electric Start?

On a Mercury 9.9 hp outboard, this comes down to your back, your battery and your budget.

Manual start is lighter, cheaper and needs no battery. Mercury’s EFI system charges itself from the pull cord, so manual-start models don’t need a cranking battery at all. A two-cylinder 9.9 is not hard to pull, especially when warm. This is the right choice for tenders and boats without a battery.

Electric start costs about $350 more in our range and needs a battery on board. It’s easier for older owners or anyone with a bad shoulder, and it’s handy for kickers and boats where you start and stop the engine a lot. If your boat already has a battery for lights or a fish finder, electric start is an easy upgrade.

We’ve written a full guide on electric start vs manual start outboard motors if you want more detail.

Choosing the Right Shaft Length

Getting the shaft right matters more than any other choice you make on a Mercury 9.9 hp outboard. Measure from the top of the transom (or the motor bracket) straight down to the bottom of the hull:

• About 15 inches: short shaft (no letter). Most inflatables, dinghies and small car-toppers.
• About 20 inches: long shaft (L). Most jon boats, aluminium skiffs and small fishing boats.
• About 25 inches: extra-long shaft (XL). Sailboats and most kicker brackets on bigger boats.

Too short and the prop sucks air and loses grip. Too long and you add drag and hit bottom in shallow water. Our guides to long shaft vs short shaft outboard motors and cavitation plate height walk you through it.

Mercury 9.9 HP Outboard vs Yamaha, Suzuki, Tohatsu and Honda

Every major brand makes a 9.9 (or 10 HP), and they’re all decent engines. Here’s how our prices compare:

Prices are close across the board, so pick on features and support. The Mercury 9.9 hp outboard stands out for its battery-free EFI on manual-start models, the Command Thrust option, and the ProKicker package for anglers. Yamaha’s T9.9 High Thrust is the closest rival to Mercury’s Command Thrust. Tohatsu has the lowest price in this table. Honda and Suzuki both have loyal followings for reliability.

The real tie-breaker is local service. Buy the brand your nearest marine mechanic works on. For deeper comparisons, read our Yamaha 9.9hp guide, Honda 9.9 guide, Tohatsu MFS9.9EEFTUL price guide, and the brand match-ups Mercury vs Suzuki, Yamaha vs Mercury and Honda vs Mercury.

Should You Go Smaller or Bigger?

The Mercury 9.9 hp outboard sits in the middle of Mercury’s small portable range. Before you settle on it, check the neighbours:

• Mercury 8 HP if you want to save a little and don’t need the extra power. Mercury’s 8 HP is tiller-only. See the 8MH ($2,560), 8MLH ($2,585) and 8ELH ($2,925), or the Mercury 8 HP category.
• Mercury 15 HP if your boat is rated for it and you want to plane a heavier load. Try the 15MH EFI ($3,130) or 15ELH EFI ($3,530). There’s also a 15 HP ProKicker ($4,190) for bigger boats. Browse the Mercury 15 HP and Mercury 20 HP ranges.
• Something smaller and lighter for a canoe or small tender. Read our lightweight outboard motors and portable outboard motors guides.
• No petrol at all. Our propane outboard motor guide and electric outboard motors guide cover the alternatives.

Not sure how much power your boat needs? Our guide on how to select the correct horsepower for your boat explains the basics.

New EFI or an Older Carburetted Mercury 9.9?

Plenty of used Mercury 9.9s are for sale, and most are older carburetted engines. They can be good value, but you should know the trade-offs before choosing a used engine over a new EFI Mercury 9.9 hp outboard.

Carburettors and stale fuel. Small carburettors have tiny passages that clog when fuel sits and goes stale. That’s the most common reason an older 9.9 won’t start in spring. The EFI models avoid this part of the problem.

Fuel economy. Mercury claims up to 27% better economy for the EFI models than the earlier carburetted ones. On a small engine that’s not a fortune, but over several seasons it adds up.

Starting. The new manual-start EFI models run with no battery. Older carburetted models also run without a battery, but they usually need a choke and some priming when cold.

Condition is everything. A used engine is only as good as its history. Ask for service records, check for corrosion and water in the gearcase oil, and run a compression test. Our used Mercury buyer’s guide covers what to look for, and we list some used outboard engines too.

If you want an engine you can rely on from day one, with no unknown history, a new Mercury 9.9 hp outboard is the safer bet.

When a Mercury 9.9 HP Outboard Isn’t the Right Choice

A 9.9 is a great size, but it’s not right for every boat:

• Your boat is rated well above 10 HP and you want speed. A 15, 20 or 25 HP will plane a loaded boat much better.
• You need to carry the engine a long way. At 88 lb or more, a 9.9 is a two-hand lift. A 2.5 to 6 HP portable is far easier. See our lightweight outboard motors guide.
• Your canoe or small inflatable is rated under 10 HP. Stay within the plate. Our outboard motors for canoes guide suggests smaller options.
• You want silence on a nature reserve. An electric motor may suit you better. Read our quietest outboard motors guide.

Fitting a Mercury 9.9 HP Outboard

Fitting a Mercury 9.9 hp outboard is a one or two-person job, depending on the version. The standard model weighs under 100 lb dry, but a ProKicker is heavier, so get help lifting it onto a high bracket.

1. Check the transom or bracket. It should be solid, with no soft spots or cracks.
2. Centre the engine and tighten the clamp screws by hand. Fit a safety cable to a strong point on the boat in case the clamps loosen.
3. Set the tilt angle so the shaft sits close to vertical with the boat at normal load.
4. Check the engine and gearcase oil before the first start. Follow the owner’s manual.
5. Connect the fuel line from the tank to the engine.
6. Clip on the kill-switch lanyard, set neutral and start.
7. Check the cooling water stream appears within a few seconds. If it doesn’t, stop the engine.

For a kicker, many owners link the kicker to the main engine’s steering with a link arm so they can steer from the helm while trolling. A marine technician can set this up. Our how to install an outboard motor guide has more detail.

Owning a Mercury 9.9 HP Outboard: Break-In and Maintenance

The EFI Mercury 9.9 hp outboard is designed to be easy to look after. Mercury cut out the oil filter and fitted a maintenance-free camshaft, according to the 2024 launch reports. Follow the maintenance schedule in your owner’s manual. The jobs that matter:

• Break-in: vary the throttle and avoid long runs at full power for the first hours. Our break-in guide explains why.
• Engine oil at the intervals in the manual.
• Gearcase oil, checked for water or metal. See our lower unit oil guide.
• Water pump impeller inspection, especially in sandy or silty water.
• Freshwater flush after salt use. The garden-hose flush fitting makes this a two-minute job.
• Spark plugs checked each season.
• Fuel: use fresh fuel, and add a stabiliser if the engine will sit for weeks. Keep water out of the tank.

Our outboard motor maintenance checklist, winterizing guide and troubleshooting guide have the full details.

Three Real Set-Ups for a Mercury 9.9 HP Outboard

Spec sheets only go so far. Here’s how we’d match a Mercury 9.9 hp outboard to three common boats. These are examples, not rules, so measure your own boat before ordering.

A 3.6-metre RIB tender behind a cruising yacht

The tender lives on deck or on davits and gets used for runs ashore, sometimes with three adults and shopping on board. It needs enough power to plane with a load, light enough weight to lift on and off the yacht, and no fuss about batteries. That points to the short-shaft, manual-start 9.9MH. Battery-free EFI means it starts with a pull even after weeks sitting on the stern rail. Use a halyard or small crane to lift it, since at around 88 lb dry it’s a lot to hand down into a moving dinghy.

A 14-foot aluminium fishing boat for two people

Two anglers, a cooler, rods and a tackle box on a lake or sheltered bay. The boat has a 20-inch transom and a small battery for a fish finder. Here a 20-inch electric-start Mercury 9.9 hp outboard like the 9.9ELH makes life easy. If the boat is a wide, flat jon boat that carries a lot of weight, step up to the Command Thrust 9.9ELH-CT for better push. If it’s a lake with a 10 HP limit, this is about as much engine as you can legally run anyway.

A 20-foot walleye or salmon boat with a big main engine

The main engine is 150 HP or more. Trolling all day on that engine burns fuel, adds hours and often can’t go slow enough. The answer is a ProKicker on a kicker bracket next to the main engine. A 25-inch 9.9EXLHPT-CT-PK is the usual choice. Power tilt lifts it clear when you run on the main engine, and a steering link lets you steer from the console while trolling. You also get a back-up engine if the main one ever lets you down far from the ramp. Our kicker motor buying guide compares the Mercury with other brands’ kickers, and our outboard motors for fishing guide covers more fishing set-ups.

Trolling With a Mercury 9.9 HP Outboard: Practical Tips

If you’re buying a ProKicker or Command Thrust model for trolling, a few habits make a big difference:

• Trim the main engine up while trolling on the kicker. It cuts drag and stops the big prop acting like a rudder.
• Use the steering link. Linking the kicker to the main engine’s steering means you can steer from the helm instead of sitting at the stern.
• Find your speeds early. Note the throttle positions that give your favourite trolling speeds on a GPS, so you can repeat them each trip.
• Keep the kicker’s fuel fresh. Kickers often sit unused for long periods. Run them regularly and keep the fuel clean.
• Check the prop. The high-thrust four-blade prop is what gives a ProKicker its grip at low speed. Keep it free of dings and fishing line.

Our guide to the best outboard motors for trolling and our propeller guide go into more depth.

Running Costs of a Mercury 9.9 HP Outboard

A small four-stroke is cheap to run, but it’s worth knowing where the money goes.

Fuel. Mercury says the EFI 9.9 uses up to 27% less fuel than its earlier carburetted models. Actual use depends on your boat, load and throttle. Running at part throttle rather than flat out saves a lot, as it does on any engine. Our fuel-efficient outboard motors guide has tips.

Servicing. Oil, gear oil, an impeller every few seasons and spark plugs. Mercury removed the oil filter and fitted a maintenance-free camshaft on the EFI models, which trims the parts list.

Extras. A spare prop, a fuel tank if yours is old, a kicker bracket or steering link for ProKicker set-ups, and safety gear. None of it is expensive on its own, but it adds up.

The biggest saving with a Mercury 9.9 hp outboard is often avoiding problems. EFI does away with the carburettor, which is the part most likely to clog on a small engine that sits unused.

Saltwater or Freshwater Use

Mercury says the 9.9 is built with saltwater-safe components and corrosion-preventative technologies. That helps, but salt still needs looking after. Flush the engine with fresh water after every salt trip using the garden-hose fitting, rinse the outside, and check the anodes. Store it upright or tilted so water drains out.

In fresh water, sand and silt are the main enemies. Check the water pump impeller more often if you launch from beaches or run in shallow, muddy water. Either way, our winterizing guide covers lay-up if your boat comes out for the cold months.

Before You Order: A Quick Checklist

Run through these and you’ll pick the right Mercury 9.9 hp outboard the first time:

• What’s your transom or bracket height: 15, 20 or 25 inches?
• What’s the maximum horsepower on your boat’s capacity plate?
• Do you need extra push for a heavy boat (Command Thrust)?
• Is it a kicker for trolling (ProKicker)?
• Manual or electric start? Do you have a battery on board?
• Any licence or horsepower rules where you boat?
• Who services Mercury engines near you?

Send us your answers and we’ll confirm the right model before you buy.

Common Mistakes When Buying a Mercury 9.9 HP Outboard

1. Wrong shaft length. This is the big one. Measure your transom before you order.
2. Buying standard when you need Command Thrust. A heavy pontoon or sailboat with a standard prop will feel underpowered.
3. Buying a ProKicker for a small boat. The ProKicker is heavier and costs more. On a tender or jon boat, the standard model is lighter and cheaper.
4. Ignoring the horsepower plate. Some small inflatables and canoes are rated below 10 HP.
5. Forgetting local rules. Check licensing and horsepower limits for your country and the lakes you use.
6. Budgeting only for the engine. Fuel tank, safety gear, a kicker bracket or steering link can add to the cost. See our hidden costs guide.

Buying a Mercury 9.9 HP Outboard From Us

Every Mercury 9.9 hp outboard listed here is new. Our shipping policy says orders normally ship within 1 to 6 business days with free delivery, and you’ll get a tracking email once your engine is on its way. You can follow it on the order tracking page. Import duties and taxes depend on your country, so check with your local customs office first.

Useful reading before you buy:

• Outboard motors worldwide shipping, step by step
• Cost of shipping an outboard motor internationally
• Outboard motors with warranty: what’s covered
• Can you finance an outboard motor?
• How to make sure you’re buying genuine Mercury engines
• Our general guide to buying Mercury outboards
• Used Mercury outboard motors for sale

Not sure which Mercury 9.9 hp outboard to choose? Contact us with your boat’s make, length, transom height and what you’ll use it for, and we’ll recommend the right model. You can also browse all Mercury outboard motors, the full shop, or our used outboard engines. Our returns and refund policy has the details on returns.

Mercury 9.9 HP Outboard FAQ

How much does a Mercury 9.9 hp outboard cost?

In our store, new prices run from $2,865 for a 15-inch manual-start 9.9MH to $3,745 for the 25-inch 9.9EXLHPT-CT-PK ProKicker. Command Thrust models sit in between, from $3,030.

How much does a Mercury 9.9 hp outboard weigh?

Current dealer specs list the standard EFI tiller at 88 to 97 lb dry and the remote Command Thrust ProKicker at 115 lb. Mercury’s earlier 333 cc ProKicker spec sheet lists 122 lb.

Is the Mercury 9.9 fuel injected?

Yes. Mercury moved its 8 and 9.9 HP FourStrokes to EFI in 2024. Older Mercury 9.9s were carburetted, and an earlier ProKicker used a 333 cc EFI engine.

Does a manual-start Mercury 9.9 need a battery?

No. Mercury says pulling the cord charges the electrical system enough to run the EFI and ignition, so manual-start models don’t need a cranking battery.

What is Command Thrust?

A larger, heavy-duty gearcase that turns a bigger propeller. It gives more push at low and mid speeds for heavy boats, pontoons, sailboats and kicker use. It doesn’t add horsepower.

What is a ProKicker?

Mercury’s kicker package: a Mercury 9.9 hp outboard with a Command Thrust gearcase, a high-thrust four-blade prop and power tilt. It’s built for slow trolling and as a back-up engine on larger fishing boats.

Why 9.9 instead of 10 HP?

In some places, 10 horsepower is a legal threshold. For example, Transport Canada requires a licence for pleasure craft powered by 10 HP or more. Some lakes also restrict engines over 10 HP. Always check local rules.

Which shaft length do I need?

Measure from the top of the transom to the bottom of the hull. About 15 inches means short shaft, 20 inches means L, and 25 inches means XL.

Can I use a Mercury 9.9 hp outboard in salt water?

Yes. Mercury says it uses saltwater-safe components and corrosion protection. Flush it with fresh water after each salt trip and check the anodes.

Is Command Thrust worth it?

If your boat is heavy, wide, a pontoon or a sailboat, usually yes. On a light tender or small skiff, the standard model is lighter and cheaper.

Do you ship a Mercury 9.9 hp outboard worldwide?

Yes. We ship worldwide with free delivery, and orders normally ship within 1 to 6 business days.

Sources and References

• Boating Industry Canada: Mercury introduces 8 and 9.9hp EFI FourStroke and 9.9hp EFI ProKicker
• BoatNews: Mercury unveils FourStroke EFI 8 and 9.9 hp and ProKicker EFI 9.9 hp
• Mercury Marine: 9.9hp EFI Tiller FourStroke Command Thrust
• Mercury 9.9 and 15hp EFI ProKicker specification sheet
• Defender: Mercury 9.9 hp tiller specifications
• Defender: Mercury 9.9 hp remote Command Thrust ProKicker specifications
• Transport Canada: pleasure craft licensing
• Missouri Department of Conservation: use of boats and motors