MERCURY 2.5 HP 2.5MH OUTBOARD MOTOR

Description

The Mercury 2.5 HP 2.5MH outboard motor is the smallest gas motor Mercury makes, and honestly it’s one of the most useful. It weighs about as much as a full bag of dog food, it carries its own fuel, and it will push an inflatable, a canoe or a little dinghy all day on a tank you could hold in one hand. We have it for sale new, with the Mercury factory warranty, and we ship it to boaters worldwide.

People usually come to this motor from one of two directions. Either they’ve been rowing and they’re done with it, or they’ve got an old two stroke kicker that stinks, leaks and won’t idle. Either way, the answer tends to be the same little grey Mercury. Below I’ll cover what it does, what it doesn’t do, and whether it’s the right size for your boat.

On this page:

• Why people buy the Mercury 2.5 HP 2.5MH outboard motor
• Reading the model code
• Boats it suits
• Running it day to day
• Features
• Specifications
• Care and maintenance
• 2.5 vs 3.5 vs 4 hp
• Price and worldwide shipping
• FAQ

Why people buy the Mercury 2.5 HP 2.5MH outboard motor

Because it’s easy. That’s really the whole story. You pick it up by the built in handle, walk it down the dock, clamp it on, pull the cord and go. There’s no battery, no remote fuel tank to haul, no wiring and no key. When you’re done you lift it off, lay it down the right way, and it goes in the boot of the car.

The Mercury 2.5 HP 2.5MH outboard motor is a single cylinder four stroke. That means quiet running, no oil mixing and no blue smoke hanging over the water. Mercury also gave it a fairly big displacement for its class, 85 cc, so it has more low down shove than some of the other small motors you’ll find at this power rating. You notice that when you’re pushing a loaded tender against a tide.

It also sips fuel. The built in tank holds about a litre, which sounds tiny until you realise how little the motor actually burns at a comfortable cruising throttle. For a trip out to a moored yacht and back, or an afternoon poking around a small lake, it’s plenty. For longer runs, carry a small jerry can.

Our typical buyers for the Mercury 2.5 HP 2.5MH outboard motor are yacht owners who need a tender motor, anglers with canoes or small inflatables, and people who live near water and just want to potter about without buying a bigger boat. It’s also a favourite for anyone with a bad back, because it’s about as light as a proper outboard gets.

Reading the model code: what “2.5MH” means

Mercury’s naming is simple once you’ve seen it a couple of times:

• 2.5 is the horsepower.
• M is manual start, a pull cord.
• H is tiller handle steering.
• No L in the code means a 15 inch short shaft.

So the 2.5MH is the short shaft, pull start, tiller version. That’s the only way the 2.5 is really sold, and it’s the right setup for the boats this motor is meant for. If you need a 20 inch long shaft at this sort of size, move up to the Mercury 3.5MLH or the 4MLH.

What boats the Mercury 2.5 HP 2.5MH outboard motor suits

Shaft length first, as always. Measure from the top of your transom straight down to the bottom of the hull. If it’s somewhere around 15 inches, the short shaft on the Mercury 2.5 HP 2.5MH outboard motor will sit at the right depth. If it’s closer to 20 inches, you need a long shaft motor, and the 2.5 isn’t it.

Boats that usually suit a 2.5:

• Inflatable dinghies and tenders up to about 2.7 to 3 metres
• Square stern canoes, or canoes fitted with a proper side bracket
• Small rowing dinghies and prams
• Light car topper boats on flat water
• Kayak and canoe outriggers set up for a small motor

What it won’t do is get a normal aluminum fishing boat on plane. It’ll move a 12 foot tinny along at a gentle displacement speed, and some people are perfectly happy with that for trolling on a calm lake. But if you want to get somewhere quickly, or you’ve got two adults and gear, look at the Mercury 6MH or the 9.9MH instead.

Always check your boat’s capacity plate or the manufacturer’s recommendation for inflatables. Most small tenders are rated well above 2.5 hp, so this motor won’t get you in trouble there.

Running the Mercury 2.5 HP 2.5MH outboard motor day to day

Starting

Open the fuel tap and the tank vent, pull the choke if it’s cold, and give it a firm pull. A healthy Mercury 2.5 HP 2.5MH outboard motor usually starts within two or three pulls cold and on the first once warm. Push the choke back in once it’s running.

Steering and reverse

This one catches people out. The 2.5 has forward and neutral only. There’s no reverse gear. Instead, the whole motor rotates a full 360 degrees on its bracket. To go backwards you swing the motor round so the prop faces forward and drive it that way. It feels odd for about five minutes and then it’s second nature. It also makes the motor very manoeuvrable around docks and moorings.

Throttle

Twist grip, with a tension adjuster. Snug it up a bit and the motor will hold its speed while you let go to bail, fish or grab a line. For a tender that’s a handy thing.

Noise and smell

The exhaust goes out under the water. Combine that with the four stroke design and the Mercury 2.5 HP 2.5MH outboard motor is genuinely quiet at low throttle. You can talk normally in the boat and you won’t come home smelling of two stroke oil.

How fast will it go?

That depends completely on the boat and the load. On a light inflatable with one person you’ll get a nice steady pace, somewhere around a brisk jog to a slow bicycle. With two adults it’s slower. I won’t give you a number, because it would only be true on one boat on one day. Full throttle runs at 5,000 to 6,000 rpm, and the motor should reach that range comfortably on a correctly loaded boat.

Features of the Mercury 2.5 HP 2.5MH outboard motor

• Compact, lightweight single cylinder four stroke
• Digital CD ignition
• High grade marine alloy construction
• Stainless steel water pump housing
• Zinc coated water passages
• Rated for saltwater use
• Sacrificial zinc anodes
• Forward and neutral gear shift
• 360 degree steering with tension adjustment
• Twist grip throttle with tension control
• Integrated carry handle
• Thermostat controlled water cooling
• Visual oil level indicator
• Over rev protection
• 4 trim positions
• Below the water exhaust
• 1.0 litre integral fuel tank
• Safety lanyard stop switch
• Owner’s manual and tool kit
• Mercury Marine 3 year warranty

The visual oil level window is one I like on a motor this size. You don’t need to dig out a dipstick and a rag. Glance at the window before you go, and if it’s low, top it up. The thermostat is another quiet benefit. It keeps the engine at a steady temperature, which helps it idle smoothly and makes it much less fussy in cold water.

Mercury 2.5 HP 2.5MH outboard motor specifications

You can compare these figures with Mercury’s own FourStroke outboard range. Mercury updates small details between model years, so if one particular spec matters to you, ask us and we’ll confirm it on the unit we ship.

Looking after your Mercury 2.5 HP 2.5MH outboard motor

Small motors mostly die from neglect, not hard work. Treat it right and the Mercury 2.5 HP 2.5MH outboard motor will run for years.

Fuel is the big one

The carburetor on a small motor has tiny jets, and stale fuel gums them up quicker than you’d think. Use fresh 87 octane unleaded with no more than 10% ethanol. If it’s going to sit for more than a few weeks, turn off the fuel tap and let it run until it stops. That empties the carb bowl. Better still, drain the tank too. This one habit prevents most “it won’t start” problems.

Oil

It only takes about 300 ml of 10W-30. Check the window before every trip. Change it after the first 20 hours, then once a season or every 100 hours.

How to lay it down

Four strokes have an oil sump, so you can’t just toss it in the car any old way. Check the owner’s manual for the correct side to lay it on. Get it wrong and oil can run where it shouldn’t, and you’ll have a smoky, hard starting motor next time.

Saltwater

If you use the Mercury 2.5 HP 2.5MH outboard motor as a tender motor on a yacht, it’s going to live in salt. Flush it with fresh water whenever you can. A bucket of fresh water and a few minutes of running at idle does the job. Keep an eye on the anodes.

Gear lube

Change the gear case oil once a year. It’s cheap and quick, and if it comes out milky you’ve caught a seal problem early.

Before your first trip, have a look at the basic safety guidance from the US Coast Guard boating safety site. It’s written for the US, but lanyards, life jackets and fuel safety are the same everywhere.

Who the Mercury 2.5 HP 2.5MH outboard motor isn’t for

If you want to plane a boat, skip it. If you regularly carry two or three adults, skip it. If you need to run long distances on open water, skip it, or at least carry spare fuel and be realistic about speed. And if you want reverse gear, that’s a 4 hp or bigger.

Where the Mercury 2.5 HP 2.5MH outboard motor shines is short trips, light boats, calm water and people who value lightness above everything. If that’s you, there isn’t a better small motor on the market for the money.

Real setups where the Mercury 2.5 HP 2.5MH outboard motor works well

It helps to picture the motor on an actual boat, so here are the setups we see most often from customers.

The yacht tender

This is probably the most common one. A cruising sailor has a 2.4 or 2.7 metre inflatable hanging off the stern or lashed on deck, and needs something to get ashore for groceries, fuel and a meal. The Mercury 2.5 HP 2.5MH outboard motor is ideal here. It’s light enough to hand down from the yacht into a bouncing dinghy without anyone getting hurt, and the built in tank means no extra fuel can rolling around the floor of the tender. Many sailors keep it on a small rail bracket on the pushpit when they’re under way.

The canoe angler

Square stern canoes and canoes with a side mount are a lovely way to fish small lakes and slow rivers. Paddling in is fine. Paddling home into a breeze after six hours of casting is less fine. A 2.5 on a canoe is quiet enough that it won’t spook the whole lake, and it’s light enough that the canoe still sits properly in the water.

The lake cabin runabout

Lots of people have a small aluminum pram or rowing boat at a cabin or holiday house. They don’t need speed. They need to cross the bay to a neighbour’s jetty or go out for an evening troll. The Mercury 2.5 HP 2.5MH outboard motor does that, then comes off the boat and lives in the shed over winter where it can’t get stolen.

The backup motor

Some owners of bigger boats carry a 2.5 as an emergency get home motor. It’s not going to set any records, but it will move a small boat slowly back to the ramp if the main engine dies. For the weight and the price, that’s cheap insurance.

Mounting the Mercury 2.5 HP 2.5MH outboard motor properly

Take your time with this the first time. Centre the motor on the transom, or on the motor mount pad on an inflatable, and tighten both clamp screws firmly by hand. Don’t use a tool on them, just a good firm twist. Then tie a lanyard or light line from the motor to a strong point on the boat. Small motors slip off transoms more often than people admit, and the bottom of a lake is a bad place to keep one.

Set the tilt pin so the motor sits upright in the water when the boat is loaded normally, with the anti ventilation plate roughly level with the bottom of the hull. The Mercury 2.5 HP 2.5MH outboard motor has four positions, so try a couple and see which gives the smoothest ride and the least splashing at the stern.

Storing it over the off season

If your Mercury 2.5 HP 2.5MH outboard motor is going to sit for a few months, a little effort now saves a headache in spring. Run it on fresh water to flush the cooling passages. Shut off the fuel and let it run dry. Drain the rest of the tank. Change the oil so fresh oil sits in the engine rather than old acidic oil. Grease the clamp screws and the swivel. Then store it upright on a stand or laid down on the correct side, somewhere dry. Come spring, add fresh fuel and it should start without fuss.

A few buyers ask whether they should fog the engine. On a motor this small, a proper run dry plus fresh oil is usually enough for normal winters. If you’re storing it for a year or more, fogging does no harm, and the owner’s manual covers how.

Mercury 2.5 vs 3.5 vs 4 hp

These three get compared all the time, so here’s the straight version.

The 2.5MH is the lightest and cheapest. Forward and neutral only, 360 degree steering for reverse. Ideal for tenders and canoes.

The 3.5MH is almost the same weight and size, with a bigger carburetor for more punch. If your boat is on the heavier side of “small”, or you use it in current or wind, the extra power is worth the small price step. It also comes in a long shaft version.

The 4MH is a different, heavier motor at around 55 lb. It has a proper forward, neutral and reverse gearbox, a pressurised oil system and an option for a small charging coil. It’s more of a small fishing boat motor than a tender motor.

Above that you’re into the 5 hp and 6 hp range. You can see all the small ones in the Mercury 4 HP section and the main Mercury outboard motors category.

Mercury 2.5 HP 2.5MH outboard motor for sale: price and worldwide shipping

The price for the Mercury 2.5 HP 2.5MH outboard motor is shown at the top of this page. Add it to your cart and check out, or if you’d prefer to talk first, message us through the contact page and we’ll give you a full delivered price to your door.

What’s in the box

• Mercury 2.5 HP 2.5MH outboard motor, new
• 3 blade composite propeller, fitted
• Built in fuel tank
• Tool kit
• Owner’s manual
• Mercury Marine 3 year factory warranty from the date of purchase

Shipping

We ship worldwide. A motor this size is easy to send: it’s boxed securely, dispatched by courier or freight, and tracked all the way. Once it leaves us you get the tracking details. Import duty and local taxes depend on where you live, and we’re happy to talk you through what to expect before you buy. Please note the motor ships dry, with no fuel in it, as the carriers require.

Buying with confidence

Have a read of our refund and return policy and the customer reviews from other boaters. The about page tells you more about who we are.

Mercury 2.5 HP 2.5MH outboard motor FAQ

Does the Mercury 2.5 HP 2.5MH outboard motor have reverse?

No. It has forward and neutral. You get reverse by turning the whole motor around 180 degrees, which the bracket allows.

Does it need a separate fuel tank?

No. The tank is built into the motor. It holds a little under a litre.

Can I use it in saltwater?

Yes. It’s saltwater rated. Flush it with fresh water after use to keep corrosion away.

Will it charge a battery?

No. There’s no charging option on the 2.5. If you need charging, look at the 4 hp or larger.

How heavy is it?

Around 40 pounds. One adult can carry it by the handle without much trouble.

Is it new?

Yes, new, with the full Mercury factory warranty.

Do you ship to my country?

We ship worldwide. Send us your location through the contact page for a delivered quote.

What oil does it take?

SAE 10W-30 four stroke outboard oil, about 300 ml.

Ready to order your Mercury 2.5 HP 2.5MH outboard motor?

If you’re after a light, quiet, dependable little motor for a tender, canoe or small inflatable, this is the one most people end up with, and for good reason. Add the Mercury 2.5 HP 2.5MH outboard motor to your cart now, or send us a question first. You can also look through the rest of our outboard motors for sale before deciding.