MERCURY 5 HP 5MH OUTBOARD MOTOR

Description

The Mercury 5 HP 5MH outboard motor is a small four stroke that punches a bit above its size. It’s got a proper forward, neutral and reverse gearbox, a bigger carburetor and propeller than the 4 hp, and a built in fuel tank so you can grab it and go. We sell it new, with the Mercury factory warranty, and ship it to buyers all over the world.

This is the motor I’d point you to if you’ve got a small skiff, a jon boat or a decent sized inflatable and you want something that’s still portable but won’t feel weak the moment you add a second person. Here’s the full rundown, including the things it isn’t so good at.

On this page:

• Why the Mercury 5 HP 5MH outboard motor
• What 5MH means
• Boats it suits
• How it runs
• Features
• Specifications
• Maintenance
• Compared with other small Mercurys
• Price and shipping
• FAQ

Why the Mercury 5 HP 5MH outboard motor

On paper, the 5 hp and the 4 hp look almost identical. Same 123 cc single cylinder, same weight of around 55 pounds, same gearbox and oil system. The difference is in the breathing and the prop. Mercury fitted the 5 hp with a larger carburetor and a propeller with a bit more pitch, and together those turn into more speed and more push on the water.

For most buyers, that makes the Mercury 5 HP 5MH outboard motor the sweet spot in the small portable range. It weighs no more than the 4, it’s only a small step up in price, and it gives you a little extra in reserve when the boat is loaded or conditions turn.

It’s a four stroke, so it runs on straight unleaded with no oil mixing. It’s quiet, it doesn’t smoke, and it’s easy on fuel. The built in tank holds just over a litre, and there’s a standard connection for an external tank when you want to run longer.

The people who buy the Mercury 5 HP 5MH outboard motor from us are mostly anglers with small skiffs and jon boats, owners of larger inflatables and RIBs, and people who need a dependable little motor for a lake, a river or sheltered coastal water.

What “5MH” means

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

The 5 hp comes in quite a few versions. There’s the 5MXLH with a 25 inch extra long shaft, the 5MLHA Sail Power for sailboats, and propane versions like the 5MH-LPG. This page is about the standard short shaft gasoline model.

Boats the Mercury 5 HP 5MH outboard motor suits

First, check your shaft length. Measure from the top of the transom straight down to the bottom of the hull. About 15 inches means this short shaft Mercury 5 HP 5MH outboard motor is the right fit. About 20 inches means you’ll need a long shaft motor, and about 25 inches means extra long.

Good matches for the 5MH:

• Small skiffs and aluminum fishing boats around 10 to 12 feet
• Jon boats with low transoms
• Inflatable boats and RIBs up to around 3.5 metres
• Hard dinghies and yacht tenders
• Drift boats and small utility boats on calm water

A 5 hp will get a light inflatable with one person onto the plane in many cases, and it’ll push a small aluminum boat at a comfortable displacement speed. It won’t plane a 14 foot boat with two adults and gear. For that, you’ll be happier with the Mercury 8MH or the 9.9MH.

How the Mercury 5 HP 5MH outboard motor runs

Starting

Open the fuel vent and tap, pull the choke if it’s cold, put it in neutral and give it a firm pull. The start in gear protection stops it firing up in forward or reverse. Clip the lanyard on first. Most of the time it starts on the first or second pull.

Gears

The shift lever sits on the front of the motor, easy to reach from the tiller. Proper reverse makes launching, docking and backing off snags far easier than on the 2.5 and 3.5, which have to be spun round.

Throttle

Twist grip with a friction adjuster. Set your speed, tighten the knob a touch, and let go to net a fish or sort out a line.

Shallow water drive

Lock the motor partly tilted and you can motor slowly through shallows with the prop running higher. With six trim positions you can also set the running angle to suit your boat and load.

Noise

The exhaust goes out through the prop hub. The Mercury 5 HP 5MH outboard motor is quiet at trolling speed and pleasant to run all day.

RPM and speed

Full throttle sits at 4,500 to 5,500 rpm. I won’t quote a top speed, because it depends on your hull, load and conditions far more than on the motor.

Mercury 5 HP 5MH outboard motor features

• Compact and lightweight
• Larger carburetor and propeller than the 4 hp
• Digital CD ignition with spark advance
• High grade marine alloy construction
• Stainless steel water pump housing
• Zinc coated water passages
• Rated for saltwater use
• Sacrificial zinc anodes
• Forward, neutral and reverse gear shift
• Forward mounted gear shift selector
• Adjustable steering tension control
• Twist grip throttle with tension control
• Integrated carry handle
• Thermostat controlled water cooling
• Shallow water drive with 6 trim positions
• Quiet through propeller hub exhaust
• 1.15 litre integral fuel tank, plus external tank connection
• Start in gear protection
• Low oil pressure warning indicator
• ESG over rev protection
• Safety lanyard stop switch
• Owner’s manual
• Mercury Marine 3 year warranty

Mercury 5 HP 5MH outboard motor specifications

Mercury’s FourStroke outboard range page is a good place to see how the 5 hp fits into their lineup. If a specific detail matters to your purchase, ask us and we’ll confirm it for your unit.

Maintaining the Mercury 5 HP 5MH outboard motor

Fuel

Fresh 87 octane unleaded with no more than 10% ethanol. Old fuel is the number one cause of hard starting on small carbureted motors. Before any break of a few weeks, shut off the fuel and run the Mercury 5 HP 5MH outboard motor until it stops, so the carb bowl is empty.

Oil

About 450 ml of 10W-30. Check the dipstick before each trip. First change at 20 hours, then every 100 hours or once a year.

Gear case

Change the gear lube yearly. If it comes out milky, a seal is letting water in.

Cooling and salt

Check the telltale stream every time you start. In saltwater, flush after every outing and watch the anodes.

Carrying

Carry it upright. Lay it only on the side the owner’s manual shows.

The US Coast Guard boating safety site is a helpful read for anyone new to small boats, wherever you are in the world.

Where the Mercury 5 HP 5MH outboard motor earns its keep

The weekend skiff

Picture a 10 or 11 foot aluminum skiff that lives on a trailer or on the roof racks. Two people, a couple of rods, a small cooler, a morning on a lake or a sheltered bay. That’s the job this motor was made for. It pushes that kind of boat along at a relaxed pace, trolls smoothly for as long as you like, and backs you off the ramp with a flick of the shift lever. At the end of the day it comes off the transom and goes in the back of the car or the corner of the garage.

The bigger inflatable

Plenty of inflatables in the 3 to 3.5 metre range are rated for 5 hp or more. Put a 2.5 or 3.5 on them and they feel sluggish, especially with passengers. The extra torque and bigger prop of the 5 hp make a clear difference, and on a light inflatable with one aboard it can often lift the boat onto the plane. Reverse helps enormously when you’re coming alongside a bigger boat or a crowded jetty.

The river and canal boat

On slow rivers with low speed limits, a 5 hp is often all the power anyone needs. It’s quiet, economical, and the shallow water drive is useful near the banks and over gravel bars. With an external tank connected, you can cruise for hours.

The work boat and tender for a mooring

Boat yards, fish farms and moorings often use small skiffs to get people and gear around. A simple, reliable pull start motor with reverse, like this one, is exactly what’s wanted. Nothing to go flat, nothing complicated, and parts are easy to find almost anywhere.

Setting up and breaking in your new motor

When the Mercury 5 HP 5MH outboard motor arrives, look it over for any shipping damage and let us know straight away if there’s a problem. Check the oil on the dipstick and top up to the mark if needed. Clamp the motor to the centre of the transom, tighten both clamp screws firmly by hand, and tie a safety line from the motor to the boat.

Set the tilt pin so that the motor sits roughly vertical in the water when the boat is loaded normally. You can fine tune it later. Fill the built in tank with fresh fuel, or connect an external tank, open the vent and tap, clip the lanyard to yourself, put it in neutral and start it. Let it idle for a minute and check that the cooling water telltale is spraying.

For the first couple of hours, vary the throttle and avoid long periods at full speed. Then run it normally. Change the oil after the first 20 hours. That’s all the break in the motor needs.

Getting more range out of a tank

The built in tank is just over a litre. On a small boat at a gentle cruise that lasts longer than people expect, but for a full day you’ll want an external tank. The Mercury 5 HP 5MH outboard motor has the connection built in, so it’s simply a matter of adding a portable tank and fuel line.

The other big range saver is throttle. The last quarter of the throttle travel on a displacement boat adds very little speed but a lot of fuel use. Back off a little from full and you’ll often lose almost no speed while burning noticeably less fuel, with less noise too.

Questions people ask before buying the Mercury 5 HP 5MH outboard motor

“4 hp or 5 hp, which should I buy?”

Unless a horsepower limit forces you to 4, buy the 5. The two motors weigh the same and share the same gearbox and oil system. The Mercury 5 HP 5MH outboard motor simply breathes better and swings a prop with more pitch, so it gives you more speed and more push for a small difference in price. We sell more 5s than 4s for exactly that reason.

“Will it plane my boat?”

On a light inflatable with one person, often yes. On an aluminum skiff with two people, generally no. It’ll give you a steady displacement cruise. If planing matters, look at 8 or 9.9 hp and check your boat’s capacity plate.

“Is it easy for one person to lift?”

At about 55 pounds, most adults can carry it a short way using the built in handle. Lifting it onto a boat that’s already in the water is easier with two people, or with the boat on the trailer.

“What about propane? I’ve seen an LPG version.”

Mercury makes propane versions of the 5 hp, like the 5MH-LPG. They run from a propane cylinder, which means no gasoline to go stale and no carburetor to gum up. They make a lot of sense on lakes with fuel restrictions or for people who only use the motor now and then. If that sounds appealing, have a look at those pages or ask us.

“How long will it last?”

With fresh fuel, regular oil changes and a yearly gear lube change, a small Mercury four stroke routinely runs for many years. The motors we see come back tired are almost always ones that sat with old fuel in them or were never flushed after saltwater use.

“Can I leave it on the transom?”

Yes. Tilt it up out of the water when not in use and lock it to the boat if theft is a concern. The Mercury 5 HP 5MH outboard motor is light and valuable, so an outboard lock is a very sensible extra.

Spares and small extras worth having

Keep a spare spark plug and plug spanner, a shear pin or prop hardware, a small bottle of engine oil and a spare lanyard in a dry bag in the boat. If you run an external tank, a spare fuel line O ring is worth having too. For the season ahead, a water pump impeller at home means you can refresh it if the telltale stream ever weakens. None of this costs much, and it turns most small problems into a quick fix on the water.

Some owners also add a small motor stand at home. It makes flushing, oil changes and storage much easier, and keeps the Mercury 5 HP 5MH outboard motor upright and safe between trips.

Off season storage for the Mercury 5 HP 5MH outboard motor

If the boat is coming out of the water for winter or a long break, spend twenty minutes doing it properly. Flush the motor with fresh water, especially after saltwater use. Shut off the fuel and let the engine run until it stops, so the carburetor is empty. Drain what’s left in the built in tank. Change the engine oil, so clean oil sits in the engine rather than used oil with acids and moisture in it. Change the gear lube and look at its colour while you’re there.

Grease the swivel bracket and clamp screws. Wipe the motor down, and if you like, give the cowl a coat of wax. Then store it upright on a stand, or on the correct side as shown in the owner’s manual, in a dry place away from direct sun.

In spring, check the oil, add fresh fuel, and start it on a flushing attachment or in a barrel of water before the first trip. If you did the storage steps, it should fire up within a few pulls and be ready for another season.

Why a four stroke over an old two stroke

We still meet plenty of people with a much loved old two stroke at this size. They’re light and simple, but they need oil mixed in every tank, they smoke and smell, they’re thirstier and they’re harder to buy new in many countries. The Mercury 5 HP 5MH outboard motor runs on straight unleaded, idles smoothly, trolls quietly and uses far less fuel. After a season with it, most people don’t miss the old motor at all.

The Mercury 5 HP 5MH outboard motor compared with other small Mercurys

Versus the 4MH: same weight and gearbox, but the 5 hp has a bigger carb and prop. Unless a 4 hp limit applies to you, the 5 is usually the better buy.

Versus the 6MH: the 6 is stronger again. If your boat is at the heavier end, it’s worth considering.

Versus the 3.5MH: the 3.5 is much lighter at around 41 lb, but has no reverse gear and far less torque. It’s a tender motor rather than a fishing boat motor.

Browse the full range in our Mercury outboard motors category, including the 4 HP and 6 HP sections.

Mercury 5 HP 5MH outboard motor for sale: price and worldwide shipping

The price of the Mercury 5 HP 5MH outboard motor is shown at the top of this page. Add it to your cart, or contact us for a delivered quote to your country.

In the box

• Mercury 5 HP 5MH outboard motor, new
• 3 blade aluminum propeller, fitted
• Built in fuel tank with external tank connection
• Owner’s manual
• Mercury Marine 3 year factory warranty from the date of purchase

Shipping

We ship worldwide. The motor is packed securely, shipped dry, and sent by courier or freight with tracking. Duties and taxes vary by country, and we’ll explain what to expect before you pay.

Buying from us

Read our refund and return policy, see our customer reviews, and find out more on the about page.

Mercury 5 HP 5MH outboard motor FAQ

Does the Mercury 5 HP 5MH outboard motor have reverse?

Yes, forward, neutral and reverse.

How heavy is it?

About 55 pounds.

Can it run from an external tank?

Yes, the connection is standard.

Does it charge a battery?

Not as standard. An optional 12V 50W charging coil can be fitted.

Is it new?

Yes, brand new with the full Mercury factory warranty.

Do you ship worldwide?

Yes. Contact us with your location for a delivered price.

Order your Mercury 5 HP 5MH outboard motor

Light, strong for its size, with a real gearbox and a built in tank. The Mercury 5 HP 5MH outboard motor is one of the best value small motors we sell. Add it to your cart today, or ask us a question. You can also compare it with the rest of our outboard motors for sale.