MERCURY 25 HP 25MLHGA JET

Description

The Mercury 25 HP 25MLHGA jet is a manual start, tiller steer jet outboard for shallow water. It runs a three cylinder, 526 cc fuel injected powerhead through a jet pump with a stainless steel impeller, so there’s no prop or gearcase hanging below your hull. It has gas assisted tilt, a 15 amp charging system and a 20 inch transom height. We have it for sale new with the Mercury factory warranty and ship worldwide.

Pull start keeps it simple and dependable, which is exactly what you want far up a river or out in a marsh at dawn. If you need to get into water that’s too shallow for a prop, the Mercury 25 HP 25MLHGA jet is built for it.

On this page:

• Why the Mercury 25 HP 25MLHGA jet
• Boats and uses
• Features
• Specifications
• Jet care
• Alternatives
• Price and shipping
• FAQ

Why the Mercury 25 HP 25MLHGA jet

Rivers don’t care about your propeller. Gravel runs, rock gardens, sunken logs and sand bars all wait for a prop to hit them. A jet outboard takes the prop out of the equation. The pump sits roughly flush with the bottom of the boat, so on plane a jet boat can skim across water that would stop a prop boat dead.

The Mercury 25 HP 25MLHGA jet uses Mercury’s smooth three cylinder EFI powerhead, which starts cleanly on a pull without a choke and responds crisply to the throttle. Manual start means you can run it without relying on a battery, which many river users see as a big plus when they’re a long way from help. The 15 amp alternator is there to charge a battery if you do carry one for lights or a sounder.

The stainless steel impeller is tough. It shrugs off the sand, grit and small pebbles that get drawn through a jet in real river use, and keeps its edge far longer than aluminum.

Model code: 25 hp powerhead, M manual start, L long 20 inch transom, H tiller, GA gas assisted tilt, Jet jet drive.

Boats and uses for the Mercury 25 HP 25MLHGA jet

• Flat bottom aluminum river boats
• Waterfowl hunting boats in marshes and backwaters
• Fishing boats on shallow, rocky rivers
• Remote area work boats where simplicity matters
• Rescue boats where no exposed prop is safer

Getting a jet set up right matters. The pump intake needs to sit level with the hull bottom. If you’re moving from a prop motor, talk to us about transom height and mounting.

On the water

Clip on the lanyard, put it in neutral and pull. No choke. Get the boat on plane in deeper water before running into the shallows, and avoid idling or powering hard in very shallow water where you’ll suck up gravel. Shift and steer from the tiller. Full throttle is 5,000 to 6,000 rpm.

Buyer questions

“Manual or electric start for a river jet?”

Many river users prefer manual start for its simplicity and independence from the battery. If you’d rather push a button, the 25ELHGA Jet has electric start.

“How much performance do I lose with a jet?”

Roughly speaking, a jet delivers around 70% of the prop version’s performance. For shallow water access, it’s a trade most buyers are happy to make.

Mercury 25 HP 25MLHGA jet features

• Jet pump drive, nothing below the hull
• Stainless steel impeller
• Three cylinder, 526 cc EFI four stroke
• Manual start
• 15 amp, 186 watt charging
• Gas assisted tilt
• Tiller steering with forward, neutral and reverse
• Water cooled with thermostat
• Mercury Marine factory warranty

Mercury 25 HP 25MLHGA jet 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.

Caring for the Mercury 25 HP 25MLHGA jet

Intake grate: clear debris regularly.

Impeller clearance: check it periodically and adjust with shims as the manual shows.

Jet bearings: grease on schedule, more often in sandy water.

Engine: fresh fuel, regular oil changes and a fresh water flush after every 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.

How an outboard jet works

A jet outboard like the Mercury 25 HP 25MLHGA jet replaces the normal gearcase and propeller with a jet pump. Water is drawn up through an intake grate under the boat, accelerated by an impeller inside the pump housing, and pushed out the back as a powerful stream. There’s no propeller hanging below the hull.

That means the pump sits roughly level with the bottom of the boat, so you can run in water just inches deep: shallow rivers, rocky runs, gravel bars, flooded timber and tidal flats where a propeller would be destroyed. It’s also why jets are popular for rescue and river work, as there’s no exposed spinning prop near people in the water.

The trade off is efficiency. A jet uses some of the engine’s power to drive the pump, so a jet outboard produces less thrust than the same powerhead with a propeller. As a rule of thumb, expect roughly 70% of the prop version’s performance. Most jet buyers are happy with that, because the places they want to go simply aren’t reachable with a prop.

Jets also need a little care. Clear the intake grate of weed and debris, check the impeller clearance periodically, and grease the bearings as the owner’s manual describes. The stainless impeller Mercury uses stands up well to sand and small stones, which is exactly what river boaters run into.

Why three cylinders make a difference

Most outboards in the 15 to 20 hp class use two cylinders. Mercury’s 25 and 30 hp EFI motors, including the Mercury 25 HP 25MLHGA jet, use three. That matters more than you might think. With three cylinders, the power pulses overlap more evenly, so the engine runs noticeably smoother, with less vibration through the tiller and transom. It also idles more steadily, which you appreciate when trolling or creeping through a no wake zone.

The 526 cc displacement gives strong low end torque, so the boat gets up on the plane briskly without having to rev the engine hard. And because the engine isn’t working as hard at cruise, it tends to be quieter and more economical than a smaller engine pushed to its limit.

What electronic fuel injection means for you

The Mercury 25 HP 25MLHGA jet 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.

Trailering with your motor

Most owners of a motor like the Mercury 25 HP 25MLHGA jet 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.

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 25 HP 25MLHGA jet somewhere dry. Twenty minutes in autumn saves hours of frustration in spring.

Paperwork, warranty and keeping records

When your Mercury 25 HP 25MLHGA jet 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 25 HP 25MLHGA jet 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 25 HP 25MLHGA jet, 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 25 HP 25MLHGA jet, 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 25 HP 25MLHGA jet 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 25 HP 25MLHGA jet, 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 25 HP 25MLHGA jet, 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.

Alternatives to the Mercury 25 HP 25MLHGA jet

25ELHGA Jet: electric start version.

35ELPT Jet: more power for heavier boats.

25MLH EFI: the prop version for deeper water.

See our main Mercury outboard motors category.

Mercury 25 HP 25MLHGA jet for sale: price and worldwide shipping

The current price of the Mercury 25 HP 25MLHGA jet 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 25 HP 25MLHGA jet outboard, new
• Owner's manual
• Mercury Marine 3 year factory warranty from the date of purchase

Fuel tank can be supplied on request.

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 25 HP 25MLHGA jet FAQ

Does the Mercury 25 HP 25MLHGA jet need a battery?

No, it’s pull start with EFI.

Does it have a propeller?

No, it uses a jet pump with a stainless impeller.

How heavy is it?

About 171 pounds.

Do you ship worldwide?

Yes. Contact us for a delivered quote.

Order your Mercury 25 HP 25MLHGA jet

Simple, tough and built to go where props can’t. Add the Mercury 25 HP 25MLHGA jet to your cart now, or send us a question first. You can also compare it with the rest of our outboard motors for sale.