MERCURY 15 HP EFI 15MLH OUTBOARD MOTOR

Description

The Mercury 15 HP EFI 15MLH outboard motor is a fuel injected, pull start 15 hp on a 20 inch long shaft. It uses Mercury’s big 333 cc twin cylinder powerhead, weighs about 107 pounds, starts without a battery and comes with a 3.2 gallon fuel tank. It’s a strong, simple motor for long shaft jon boats, skiffs, small pontoons and sailboats. We have it for sale new with the Mercury factory warranty and ship worldwide.

If your transom is 20 inches, your boat is rated for 15 hp and you want the torque to plane a loaded boat without the complication of a battery, the Mercury 15 HP EFI 15MLH outboard motor is a great fit.

On this page:

• Why the Mercury 15 HP EFI 15MLH outboard motor
• Boats it suits
• Features
• Specifications
• Maintenance
• Alternatives
• Price and shipping
• FAQ

Why the Mercury 15 HP EFI 15MLH outboard motor

Torque and simplicity. The 333 cc twin is the largest displacement engine in its class, and it makes plenty of low down pull. That’s what gets a 14 to 16 foot jon boat or skiff onto the plane quickly with two people and gear, and what keeps a small pontoon moving steadily with the family aboard.

Electronic fuel injection makes it easy to live with. There’s no choke. Pull the cord and it fires, hot or cold. The EFI draws the power it needs from the pull of the cord, so there’s no battery to buy, charge or maintain. The system meters fuel precisely, which means cleaner running, a smoother idle and better fuel economy than an old carbureted motor.

You also get the adjustable, ambidextrous tiller handle, a wishbone engine mount that soaks up vibration, an easy canister oil filter, a tuned intake for quick throttle response, shallow water drive and a quiet exhaust through the prop hub.

Model code: 15 hp, M manual start, L 20 inch long shaft, H tiller, EFI electronic fuel injection. The short shaft version is the 15MH, and the electric start long shaft is the 15ELH.

Boats the Mercury 15 HP EFI 15MLH outboard motor suits

Measure from the top of the transom or bracket down to the bottom of the hull. About 20 inches means this long shaft is right. About 15 inches means the 15MH. Check your capacity plate for the maximum horsepower rating.

• Long shaft jon boats, 14 to 16 feet
• Aluminum skiffs with a 20 inch transom
• Small pontoon boats
• Trailer sailers and small keelboats
• Work boats and utility boats

On the water

Clip on the lanyard, put it in neutral and pull. No choke. It settles into a smooth idle, shifts cleanly through the tiller, and pulls strongly from low rpm. The full throttle range on this model is listed at 5,400 to 5,600 rpm.

Buyer questions

“Is it a good sailboat motor?”

Yes, on mid size trailer sailers and keelboats rated for 15 hp. It gives plenty of reserve against wind and tide. Note that it doesn’t charge a battery as a manual start model, so if you need charging, choose the electric start 15ELH.

“Will it plane my 16 foot jon boat?”

With one or two people and moderate gear on a typical 16 foot aluminum jon boat, generally yes.

Mercury 15 HP EFI 15MLH outboard motor features

• Large 333 cc twin cylinder powerhead
• Electronic fuel injection, battery free starting
• 20 inch long shaft
• Adjustable, ambidextrous tiller handle
• Tuned intake for quick acceleration
• Wishbone mount for reduced vibration
• Easy maintenance canister oil filter
• 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
• 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 15 HP EFI 15MLH 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 15 HP EFI 15MLH outboard motor

Fuel: fresh 87 octane, up to 10% ethanol.

Oil: about 1 quart (1000 ml) of 10W-30. Check before each trip; change oil and canister filter at 20 hours, then every 100 hours or yearly.

Gear case: change the 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 electronic fuel injection means for you

The Mercury 15 HP EFI 15MLH outboard motor uses electronic fuel injection, or EFI, instead of a carburetor. In plain terms, a small computer measures things like air temperature and engine load and injects exactly the right amount of fuel every time. You don’t need to fiddle with a choke. It starts easily whether it’s a frosty morning or a hot afternoon, it idles smoothly, and it responds cleanly when you open the throttle.

EFI is also less fussy about sitting. Carburetors have tiny jets and a fuel bowl that gum up when old fuel evaporates inside them. A sealed injection system is much more tolerant, although fresh fuel is still the best policy. And because the fuel is metered precisely, EFI motors tend to be more economical, which means more time on the water per tank.

Mercury’s small EFI engines can even start and run without a battery on manual start models: the pull of the cord generates enough power for the fuel injection system to fire. That’s a clever bit of engineering, and it means you get the benefits of EFI without having to carry a battery if you don’t want to.

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 15 HP EFI 15MLH outboard motor somewhere dry. Twenty minutes in autumn saves hours of frustration in spring.

Paperwork, warranty and keeping records

When your Mercury 15 HP EFI 15MLH 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 15 HP EFI 15MLH 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 15 HP EFI 15MLH 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 15 HP EFI 15MLH 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 15 HP EFI 15MLH 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 15 HP EFI 15MLH 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 15 HP EFI 15MLH 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 15 HP EFI 15MLH outboard motor

The duck and fishing jon boat

A 16 foot jon boat with a 20 inch transom, used year round. The Mercury 15 HP EFI 15MLH outboard motor starts easily on cold mornings thanks to EFI, and there’s no battery to die in the cold. The big displacement gets a loaded boat moving quickly.

The trailer sailer

A 22 to 24 foot trailer sailer rated for 15 hp. Plenty of reserve for tidal rivers and headwinds, with easy pull starting and no battery wiring to the stern.

The small pontoon

A 16 to 18 foot pontoon for family cruising. Smooth, quiet, economical, and simple to start for anyone on board.

Setting up

At about 107 pounds, lift it with help. Centre it on the transom, tighten both clamp screws firmly and tie a safety line to the boat. Set trim so it runs near vertical. Connect and prime the fuel line, check the oil, clip on the lanyard, put it in neutral and pull. Check the telltale and follow the break in guidance.

Trailering with your motor

Most owners of a motor like the Mercury 15 HP EFI 15MLH 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 15 HP EFI 15MLH outboard motor

15ELH EFI: electric start with a 12 amp charging system.

20MLH EFI: the same package tuned for 20 hp.

9.9MLH: lighter, for boats or waters limited to under 10 hp.

See the full range in our Mercury 15 HP section and main Mercury outboard motors category.

Mercury 15 HP EFI 15MLH outboard motor for sale: price and worldwide shipping

The current price of the Mercury 15 HP EFI 15MLH 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 15 HP EFI 15MLH outboard motor, new
• 3.2 gallon fuel tank and quick connect fuel line
• 3 blade aluminum propeller, fitted
• Owner's manual
• Mercury Marine 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 15 HP EFI 15MLH outboard motor FAQ

Does the Mercury 15 HP EFI 15MLH outboard motor need a battery?

No, the EFI runs from the pull start.

What shaft length?

20 inches, long shaft.

How heavy is it?

About 107 pounds.

Is it new?

Yes, with the Mercury factory warranty.

Do you ship worldwide?

Yes. Contact us for a delivered quote.

Order your Mercury 15 HP EFI 15MLH outboard motor

Long shaft, big torque and easy EFI starting, with no battery to worry about. Add the Mercury 15 HP EFI 15MLH 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.