MERCURY 9.9 HP 9.9MXLH-CT OUTBOARD MOTOR

Description

The Mercury 9.9 HP 9.9MXLH-CT outboard motor combines a 25 inch extra long shaft with the Command Thrust lower unit and a simple pull start. That makes it one of the best value auxiliaries around for heavy sailboats, catamarans and houseboats that mount their motor high and need real push at low speed. It comes with a 3.2 gallon fuel tank and the Mercury factory warranty. We have it for sale new and ship worldwide.

If your boat is heavy, your motor bracket sits high, and you’d rather not deal with batteries and wiring at the stern, this is probably the motor you’ve been looking for.

On this page:

• Why the Mercury 9.9 HP 9.9MXLH-CT outboard motor
• Boats it suits
• Features
• Specifications
• Maintenance
• Alternatives
• Price and shipping
• FAQ

Why the Mercury 9.9 HP 9.9MXLH-CT outboard motor

Heavy boats with high motor mounts have two problems at once. The prop sits too close to the surface, so it ventilates when the stern lifts. And a standard prop can’t grip enough water to push a heavy hull well at displacement speed. The Mercury 9.9 HP 9.9MXLH-CT outboard motor tackles both.

The 25 inch shaft puts the prop down where it stays in solid water. The Command Thrust gearcase adds another few inches of depth, and its oversized anti ventilation plate helps stop air being sucked into the prop. Inside, a 2.42:1 gear ratio drives a 4 blade high thrust prop that’s around 20% larger than standard. The result is strong, steady thrust that moves heavy boats confidently, holds slow speeds without surging and stops the boat firmly in reverse.

Pull start keeps the motor simple and affordable. You still get the smooth 208 cc twin cylinder engine, the one handed multi-function tiller, auto ratchet trim, shallow water drive and a quiet exhaust through the prop hub. The motor weighs about 99 pounds.

Model code: 9.9 hp, M manual start, XL 25 inch shaft, H tiller, CT Command Thrust.

Boats the Mercury 9.9 HP 9.9MXLH-CT outboard motor suits

With your bracket lowered, measure from where the motor clamps down to the waterline. Around 25 inches means this model. Around 20 inches means the 9.9MLH-CT.

• Heavier cruising sailboats with a high stern bracket
• Catamarans with the motor mounted between the hulls
• Houseboats and pontoon style cruisers with a tall transom
• Barges, punts and heavy work boats

On the water

Clip on the lanyard, put it in neutral, set the choke and pull. On a heavy boat, the first thing you notice is how firmly it pulls away from the dock. It holds a steady low speed in a crosswind, and a short burst of reverse actually stops the boat. The extra long leg keeps the prop biting even when the stern pitches in a swell. Full throttle is 5,000 to 6,000 rpm.

Buyer questions

“Will it push my 26 foot sailboat?”

For many sailboats in that size range, yes, especially in sheltered and coastal waters. For heavier boats or exposed passages, consider more power. Tell us your boat and we’ll give you an honest answer.

“Why not electric start?”

If you’d like electric start and charging with the same shaft and gearcase, choose the 9.9EXLH-CT. The manual start version is lighter and cheaper, with no battery to look after.

“Can I add charging later?”

Yes, an optional 12 volt, 76 watt charging kit can be fitted to the Mercury 9.9 HP 9.9MXLH-CT outboard motor.

Mercury 9.9 HP 9.9MXLH-CT outboard motor features

• 25 inch extra long shaft
• Command Thrust lower unit, 2.42:1 ratio
• 4 blade high thrust propeller
• Oversized anti ventilation plate
• Designed for heavy applications
• Manual start, no battery needed
• Digital CD ignition with spark advance
• Stainless steel water pump housing
• Zinc coated water passages, saltwater rated
• Sacrificial zinc anodes and trim tab
• Tiller integrated forward, neutral and reverse
• Twist grip throttle with tension control
• Thermostat controlled cooling
• Auto ratchet trim (5 positions) and shallow water drive
• Quiet through prop hub exhaust
• 3.2 gallon fuel tank and line
• Start in gear protection, low oil pressure warning, ESG over rev protection
• Mercury Marine 3 year warranty

Mercury 9.9 HP 9.9MXLH-CT outboard motor specifications

For the manufacturer’s own overview of the range, see Mercury’s FourStroke outboards page. Mercury updates details between model years, so if one spec really matters to your purchase, ask us and we’ll confirm it on the exact unit we ship.

Maintaining the Mercury 9.9 HP 9.9MXLH-CT outboard motor

Fuel: fresh 87 octane, up to 10% ethanol; run the carb dry before long breaks.

Oil: about 800 ml of 10W-30; check before each trip, change at 20 hours then every 100 hours or yearly.

Gear case: change the Command Thrust gear lube yearly.

Cooling: check the telltale every start; flush after saltwater use.

If you’re newer to boating, the US Coast Guard boating safety site is worth a read. It’s written for US boaters, but the advice on kill cords, life jackets, fuel handling and navigation rules applies wherever you are in the world.

What Command Thrust actually does

Command Thrust is Mercury’s name for a heavier duty lower unit fitted to some small and mid size outboards. On the Mercury 9.9 HP 9.9MXLH-CT outboard motor it brings three changes. First, a bigger gearcase with a lower 2.42:1 gear ratio, so the propeller turns slower but with much more torque. Second, a larger 4 blade high thrust propeller, around 20% bigger than the standard prop, which grabs more water. Third, an oversized anti ventilation plate and a taller gearcase that put the prop deeper below the turbulent water at the stern, so it keeps its grip.

The result is a motor that pushes heavy, wide boats with far more authority, holds a steady low trolling speed, stops and reverses more positively, and copes better when the stern pitches in a swell. You give up a little top speed on light boats, which is why Command Thrust models are aimed at sailboats, pontoons, heavier jon boats and kicker use rather than light planing skiffs.

Using your motor through the seasons

In spring, check the oil, fit fresh fuel, look over the fuel line and connectors for cracks, and run the engine on a flushing attachment or in a test tank before the first real trip. Look for a strong cooling stream and a smooth idle.

Through summer, the main jobs are fresh fuel, regular oil checks and rinsing after saltwater use. Keep an eye on the propeller for dings. A damaged prop costs you speed and fuel, and can cause vibration.

In autumn, before the boat is laid up, do the full storage routine: flush, change the oil and gear lube, deal with the fuel system as the owner’s manual describes, grease the moving parts and store the Mercury 9.9 HP 9.9MXLH-CT outboard motor somewhere dry. Twenty minutes in autumn saves hours of frustration in spring.

Paperwork, warranty and keeping records

When your Mercury 9.9 HP 9.9MXLH-CT outboard motor arrives, write down the serial number and keep it with your invoice. Take a photo of the serial plate on your phone too. If you ever need warranty work, a dealer will ask for both, and it makes the process much quicker. The Mercury factory warranty starts from the date of purchase, so hang on to that paperwork.

It is also worth keeping a simple log: date, engine hours if you have them, oil changes, gear lube changes, impeller replacements and anything unusual you noticed. It takes seconds after each service, and it adds real value if you ever sell the boat. Buyers pay more for an engine with a clear service history, and it helps any mechanic you work with understand the motor quickly.

Check your boat insurance as well. Many policies have specific requirements for outboard security, such as a lock on the clamps or bracket, and some ask for the serial number. Better to sort that out on day one than find out after a problem.

Why buy from us

We deal in outboard motors every day, and we would rather give you a straight answer than make a quick sale. If you are not sure the Mercury 9.9 HP 9.9MXLH-CT outboard motor is the right motor for your boat, message us with the make, model and length of the boat, how you use it and where you boat. We will tell you honestly whether it is a good match or whether something else would suit you better.

Every motor is packed carefully for the journey, and we keep you updated from dispatch to delivery with tracking. We ship worldwide, and we are happy to explain in advance what to expect with import duties and local taxes in your country, so there are no surprises when it arrives.

After you buy, we are still here. If you have questions about setup, break in or maintenance, just ask.

A small spares kit worth carrying

You do not need a workshop on board, but a few cheap parts turn most breakdowns into a ten minute fix. For the Mercury 9.9 HP 9.9MXLH-CT outboard motor, we suggest a spare spark plug and the right spanner, spare propeller hardware, a spare kill cord, a small bottle of engine oil, a couple of fuses if the motor has electrics, and a fuel line O ring or connector seal. Add some cable ties, a roll of self amalgamating tape and a basic multi tool.

Pack it all in a small dry bag, keep it in the boat, and check it every spring. Most owners never need it. The ones who do are very glad it was there.

A quick checklist before every trip

It sounds obvious, but most days that go wrong on the water start with something small that got missed at the dock. Before you head out with your Mercury 9.9 HP 9.9MXLH-CT outboard motor, run through this in your head:

• Enough fresh fuel for the trip, plus a sensible margin
• Engine oil checked and at the right level
• Motor mounted securely and everything tight
• Kill cord clipped to you, not left on the tiller or dash
• Cooling telltale spraying water once the engine is running
• Life jackets, a way to call for help, and a small spares kit aboard

It takes a minute or two. It is also the habit that separates relaxed boat owners from the ones waiting for a tow.

More questions we get asked

Can I install the Mercury 9.9 HP 9.9MXLH-CT outboard motor myself?

Many owners do, following the owner’s manual. If you are not confident with mounting, rigging or electrics, a local marine mechanic can set it up quickly, and it is money well spent.

How often does it need servicing?

Check the oil before every trip. Change the engine oil and gear lube at least once a year, or at the hour intervals in the owner’s manual, whichever comes first. Inspect the water pump impeller regularly and replace it as recommended.

What fuel should I use?

Fresh unleaded petrol of the octane rating shown in the specifications, with no more than 10% ethanol, unless it is a propane model. Old fuel is the cause of most running problems.

Can I pay in instalments?

Payment options vary by country. Contact us and we will tell you what is available for your order.

Why fuel care matters so much

If there’s one thing that decides whether an outboard starts first time or leaves you pulling and swearing at the ramp, it’s fuel. Modern petrol, especially with ethanol blended in, starts to break down within weeks. It absorbs moisture, separates and leaves gummy deposits that block the tiny passages in fuel systems.

For your Mercury 9.9 HP 9.9MXLH-CT outboard motor, the rules are simple. Buy fresh fuel from a busy station. Don’t store it for months in a can. Keep the tank vent closed when the boat isn’t in use. Use a fuel stabiliser if the boat will sit for more than a few weeks. And before any long lay up, deal with the fuel system as the owner’s manual describes, rather than leaving old fuel inside the engine. It’s a few minutes of effort that saves a lot of cost and frustration.

Your first run

The first hours of a new engine matter. For your Mercury 9.9 HP 9.9MXLH-CT outboard motor, follow the break in guidance in the owner’s manual. In broad terms: run at varied speeds, avoid long periods at full throttle, and don’t let it idle for ages either. Keep an eye on the cooling telltale and gauges, and listen for anything unusual.

After the break in period, change the engine oil and filter if fitted, and check the gear lube. From then on, just use it and service it on schedule. A well run in engine rewards you with smoother running and a longer life.

Real world setups for the Mercury 9.9 HP 9.9MXLH-CT outboard motor

The heavy cruising sailboat

A 25 foot sailboat with a high stern bracket, full cruising gear and a couple of crew aboard. The Mercury 9.9 HP 9.9MXLH-CT outboard motor reaches deep enough to stay biting in a swell, and the Command Thrust prop moves the heavy hull into a breeze where a standard 9.9 would slip and race.

The cruising catamaran

A small cruising cat with the motor on a crossbeam bracket. Catamarans carry a lot of windage, and the high thrust prop keeps them moving and manoeuvrable in a breeze.

The river houseboat

A small houseboat with a high stern deck and plenty of weight. The long leg reaches the water and the big 4 blade prop keeps the boat under control in current and wind.

Setting up

At about 99 pounds with a long leg, use two people or a hoist. Check there’s room for the leg below the bracket when raised. Clamp the motor on, tighten both clamp screws firmly by hand and tie a safety line to the boat. Steer through the full range to check clearances. Connect and prime the fuel, check the oil, clip on the lanyard, put it in neutral, set the choke and pull. Check the telltale and vary the throttle for the first couple of hours.

Trailering with your motor

Most owners of a motor like the Mercury 9.9 HP 9.9MXLH-CT outboard motor leave it on the boat and trailer them together. A few habits protect the motor on the road. Use a transom saver or motor support bracket where recommended, so the motor isn’t bouncing on its tilt mechanism over bumps. Make sure there’s good ground clearance under the skeg. Close the fuel vent and disconnect the fuel line. And check the motor mounting bolts or clamps before every trip, because vibration on the road can loosen them over time.

At the ramp, lower the motor only once there’s enough water under it, and raise it before you drive the boat onto the trailer. It sounds obvious, but a surprising number of skegs and props get damaged at the ramp rather than out on the water.

Alternatives to the Mercury 9.9 HP 9.9MXLH-CT outboard motor

9.9EXLH-CT: electric start and charging.

9.9EXLHPT-CT-PK: adds power tilt and a heavy duty bracket.

9.9MXLH: standard gearcase for lighter boats.

See the full range in our Mercury 9.9 HP section and main Mercury outboard motors category.

Mercury 9.9 HP 9.9MXLH-CT outboard motor for sale: price and worldwide shipping

The current price of the Mercury 9.9 HP 9.9MXLH-CT outboard motor is shown at the top of this page. You can add it to your cart and check out straight away, or if you’d rather talk to a person first, send us a message through our contact page and we’ll come back to you with a full delivered price to your country.

What you get

• Mercury 9.9 HP 9.9MXLH-CT outboard motor, new
• 3.2 gallon fuel tank and quick connect fuel line
• Command Thrust 4 blade propeller, fitted
• Owner's manual
• Mercury Marine 3 year factory warranty from the date of purchase

Shipping worldwide

We ship to buyers all over the world. Every motor is packed securely for the journey and sent by courier, freight or sea depending on its size and where you are, with tracking from dispatch to delivery. Import duty and local taxes depend on your country, and we’re happy to explain what to expect before you pay so there are no surprises.

Buying with confidence

Have a read of our refund and return policy, see what other boat owners have said on our customer reviews page, and find out more about who we are on the about page.

Mercury 9.9 HP 9.9MXLH-CT outboard motor FAQ

What shaft length is the Mercury 9.9 HP 9.9MXLH-CT outboard motor?

25 inches, extra long.

Does it need a battery?

No, it’s pull start.

How heavy is it?

About 99 pounds.

Is it new?

Yes, with the full Mercury factory warranty.

Do you ship worldwide?

Yes. Contact us for a delivered quote.

Order your Mercury 9.9 HP 9.9MXLH-CT outboard motor

Extra reach and Command Thrust pulling power, with a simple pull start. Add the Mercury 9.9 HP 9.9MXLH-CT outboard motor to your cart now, or send us a question first. You can also compare it with the rest of our outboard motors for sale.