MERCURY 6 HP 6MLH OUTBOARD MOTOR

Description

The Mercury 6 HP 6MLH outboard motor is a 20 inch long shaft, pull start, tiller steer four stroke with its own built in fuel tank and a real forward, neutral and reverse gearbox. At about 58 pounds, it’s the most powerful long shaft motor in Mercury’s lightweight single cylinder range, and it’s a favourite auxiliary for small sailboats and a handy motor for taller transom skiffs, jon boats and inflatables. We have it for sale new, with the Mercury factory warranty, and we ship worldwide.

If your boat needs a long shaft and you want the most push you can get without moving up to a heavy twin, you’re looking at the right motor. Here’s everything you need to know about the Mercury 6 HP 6MLH outboard motor before you buy.

On this page:

• Why the Mercury 6 HP 6MLH outboard motor
• Long shaft: is it right for you?
• As a sailboat auxiliary
• Other boats it suits
• On the water
• Features
• Specifications
• Maintenance
• Alternatives
• Price and shipping
• FAQ

Why the Mercury 6 HP 6MLH outboard motor

Because it gives you the most power in the light, single cylinder class, with a long shaft, without asking you to carry a heavy twin cylinder motor and a separate fuel tank. The Mercury 6 HP 6MLH outboard motor uses the proven 123 cc four stroke single, tuned to run at 5,000 to 6,000 rpm at full throttle, a little higher than the 4 and 5 hp. That extra rev range is where the extra power comes from.

It has a pressurised wet sump oil system with a low oil pressure warning, a thermostat for smooth running in cold water, and a quiet through the prop exhaust. The built in tank is handy for short trips and there’s a standard connection for an external tank when you want to go further.

Most of our buyers for this motor are sailboat owners, but we also sell plenty to people with long shaft jon boats, skiffs and inflatables who want a motor they can still lift by hand.

Long shaft: is it right for you?

Measure from the top of the transom or bracket down to the bottom of the hull. About 20 inches means this long shaft Mercury 6 HP 6MLH outboard motor is right. About 15 inches means you want the short shaft 6MH. About 25 inches means extra long, such as the 5MXLH or the 9.9MXLH.

On a bracket, lower it to the working position. You want the motor’s anti ventilation plate a few inches under the surface with the boat loaded. If you’re not sure, send us a photo with a tape measure in it through the contact page.

The Mercury 6 HP 6MLH outboard motor on a sailboat

For day sailers, small keelboats and trailer sailers, 6 hp is a comfortable amount of power. It gets you out of harbour briskly, holds the bow into wind while you hoist sails, and brings you home against a moderate breeze and tide with something in reserve. On heavier trailer sailers, the jump from 4 or 5 hp to 6 is noticeable when conditions turn.

The reverse gear makes docking far less stressful than with a motor you have to spin round. The front mounted lever is easy to reach from the cockpit. Steering tension lets you lock the motor straight and steer with the rudder once you’re under way.

If battery charging is a priority, note that the Mercury 6 HP 6MLH outboard motor doesn’t charge as standard, but an optional 12 volt, 50 watt coil can be fitted. If your boat is heavy and you mostly motor at displacement speed, also look at the high thrust 5MLHA Sail Power, which trades a little horsepower for a prop designed specifically for sailboats, plus built in charging.

Other boats the Mercury 6 HP 6MLH outboard motor suits

• Long shaft jon boats
• Skiffs and utility boats with a 20 inch transom
• Inflatables and RIBs built for a long shaft motor
• Small pontoon style boats on calm water
• River and canal boats with a taller stern

For planing a 14 foot aluminum boat with two adults, you’ll be happier with the 8MLH or 9.9MLH.

On the water

Starting

Open the fuel vent and tap, set the choke when cold, put it in neutral, clip on the lanyard and pull. Start in gear protection prevents it starting in gear.

Shifting and throttle

Forward, neutral and reverse on a front mounted lever. Twist grip throttle with friction control so you can set a speed and let go.

Shallow water drive

Six trim positions and a shallow water setting for creeping into thin water.

Noise

The exhaust leaves through the prop hub, so the Mercury 6 HP 6MLH outboard motor is quiet and keeps fumes out of the cockpit.

RPM

Full throttle is 5,000 to 6,000 rpm. Speed depends on your boat and load.

Mercury 6 HP 6MLH outboard motor features

• 20 inch long shaft
• Compact and lightweight, about 58 lb
• 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 with 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 6 HP 6MLH outboard motor specifications

For the manufacturer’s overview, see Mercury’s FourStroke outboards page. We can confirm any detail for your unit.

Maintaining the Mercury 6 HP 6MLH outboard motor

Fuel: fresh 87 octane with no more than 10% ethanol. Sailboat auxiliaries sit a lot, so buy small amounts and run the carb dry before any long break.

Oil: about 450 ml of 10W-30. Check it before each trip, change it at 20 hours and then every 100 hours or yearly.

Gear case: change the lube yearly and look for milky lube.

Cooling and salt: check the telltale on every start, rinse with fresh water and check the anodes.

On a bracket: lift the motor clear when sailing to cut drag and prevent growth.

For general safety, see the US Coast Guard boating safety site.

Questions sailors and skiff owners ask us

“5 hp or 6 hp for my trailer sailer?”

If the boat is light and you sail in sheltered water, either will do. If it’s on the heavier side, or you deal with tides and wind against you, the extra rev range of the 6 gives you more in reserve when you need it. The weight difference is tiny, so most sailors who aren’t limited by rules go for the 6.

“Is it too heavy to lift onto my bracket?”

At about 58 pounds, most adults can manage it using the carry handle. If your stern rail is high or the bracket awkward to reach, a second person or a simple lifting strap makes it easy and safe. Always tie a safety line to the motor before you lift it over the stern.

“How long does the built in tank last?”

It holds a little over a litre, which is fine for getting in and out of harbour. For long motoring legs, connect an external tank using the standard connection. Many sailors keep a small portable tank in a cockpit locker for exactly this.

“Will it charge my battery?”

Not out of the box. You can fit Mercury’s optional 12 volt, 50 watt charging coil, or pair the motor with a small solar panel. If charging is essential and your boat is heavy, the 5MLHA Sail Power is worth a look.

“Is it OK in saltwater?”

Yes. It’s saltwater rated with zinc anodes and coated water passages. Rinse it with fresh water whenever you can and check the anodes each season.

Installing it on a bracket or transom

Lower the bracket, lift the motor on by the handle, centre it and tighten both clamp screws firmly by hand. Tie a safety line to a strong fitting. Raise and lower the bracket and steer through the full range to check the leg clears the rudder and anything else on the stern.

Check the oil, add fresh fuel, clip on the lanyard, put it in neutral and start. Check the cooling telltale. For the first couple of hours, vary the throttle. Change the oil after 20 hours.

Getting the best from it on a sailboat

Set the bracket so the anti ventilation plate sits several inches under the water with the boat loaded. Use the tilt pin to get the motor as close to vertical as you can. Lock the steering straight once under way and steer with the rudder. When you reach the boat’s hull speed, back off the throttle, because a displacement boat won’t go meaningfully faster and you’ll only burn more fuel. Lift the motor clear when sailing.

What owners say after a season with the Mercury 6 HP 6MLH outboard motor

Sailors who stepped up from a 3.5 or 4 hp usually say the same thing first: the boat finally feels like it has enough power to deal with a headwind. The Mercury 6 HP 6MLH outboard motor keeps pushing where the smaller motors used to stall out, and the long shaft keeps the prop in the water when the stern lifts.

The second comment is about docking. Real reverse, controlled from a lever on the front of the motor, makes backing out of a berth and stopping alongside a pontoon far easier.

The third is how undemanding it is. Fresh fuel, a quick dipstick check, a rinse after salty days. Owners who stick to that tell us the Mercury 6 HP 6MLH outboard motor starts in a pull or two, season after season.

Real world setups

The day sailer

A 16 to 20 foot day boat on a bracket. The 6 hp gets it out of the marina briskly and back in against a breeze with power to spare, and weighs little enough to lift off and take home at the end of the day.

The trailer sailer

A 20 to 24 foot trailer sailer with a small cabin. On heavier boats in this range, 6 hp is often the minimum we’d suggest. The Mercury 6 HP 6MLH outboard motor gives you reliable harbour power and enough reserve for tidal rivers and estuaries.

The long shaft jon boat

Some jon boats have a 20 inch transom. The 6MLH gives them a light, strong motor that one person can carry, with shallow water drive for creeping over bars and weed beds.

Off season storage

Flush with fresh water, run the carb dry, drain the tank, change the oil and gear lube, grease the swivel and clamp screws, and store the motor upright or on its correct side somewhere dry. In spring, add fresh fuel, check the oil and you’re ready.

Spares and security

Carry a spare plug and spanner, prop hardware, a spare lanyard, a little engine oil and a fuel line O ring in a dry bag. Fit a lock over the clamp screws if the motor lives on the boat, record the serial number, and take the motor home if you’ll be away for long. Small outboards are popular with thieves, so a little care goes a long way.

Why a single cylinder long shaft instead of a twin

People sometimes ask why they shouldn’t just buy the 8 or 9.9 hp twin for their sailboat. The twins are smoother and stronger, and on a bigger or heavier boat they’re the right choice. But there are good reasons many small boat owners stick with the Mercury 6 HP 6MLH outboard motor.

Weight. At around 58 pounds, it’s about 25 to 35 pounds lighter than the long shaft twins. On a small sailboat, that weight sits right at the stern, where it affects trim. It also makes lifting the motor on and off the bracket much easier.

Built in fuel. The twins run from a separate remote tank. The 6 carries its own fuel, which keeps a small cockpit tidier. You can still add an external tank when you need range.

Cost. The single cylinder motors cost noticeably less to buy, and maintenance parts are cheaper too.

Enough is enough. A sailboat can only go as fast as its hull allows. If 6 hp already gets your boat to hull speed in normal conditions, extra horsepower adds weight and cost without adding much speed.

Where the twins win is on heavier boats, exposed waters and anywhere you need electric start and serious battery charging. If that’s your situation, look at the 8ELH or 9.9ELH. For most small sailboats, though, the Mercury 6 HP 6MLH outboard motor hits the sweet spot.

Fuel use and range

At a sensible cruise, the Mercury 6 HP 6MLH outboard motor is very economical. The built in tank covers short harbour runs, and a small external tank gives you hours of motoring. Back off once you reach hull speed and you’ll stretch it further still.

First run and break in

Once the motor is on the boat and the oil checked, fill the built in tank with fresh fuel or connect an external tank. Open the tank vent and fuel tap, put the shift lever in neutral and set the choke if the engine is cold. Clip the kill cord to your wrist or life jacket and give the starter cord a steady pull. When it fires, ease the choke back in as it warms and check the cooling telltale is spraying water.

For the first hour or two, keep the throttle moving. Run at different speeds and avoid long spells at full throttle. This lets the rings and bearings settle in properly. After that, you can use the motor as normal. Change the oil after the first 20 hours to clear out anything left from manufacture.

Keep your purchase paperwork and a note of the serial number somewhere safe. If you ever need warranty work, it makes things much quicker. The Mercury factory warranty runs for three years from the date of purchase.

A small checklist before every trip

• Enough fresh fuel for the trip, plus a margin
• Oil level checked on the dipstick
• Clamp screws tight and safety line attached
• Kill cord attached to you
• Cooling telltale spraying after start
• Spares bag aboard

It takes a minute or two, and it’s the best habit any small boat owner can have.

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 6 HP 6MLH 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.

Alternatives to the Mercury 6 HP 6MLH outboard motor

6MH: the same motor with a 15 inch short shaft.

5MLHA Sail Power: high thrust prop and built in charging, designed for sailboats.

4MLH: less power, similar weight, lower price.

8MLH: twin cylinder, more power, heavier, with a separate tank.

See the whole range in our Mercury 6 HP section and the main Mercury outboard motors category.

Mercury 6 HP 6MLH outboard motor for sale: price and worldwide shipping

The price of the Mercury 6 HP 6MLH outboard motor is at the top of this page. Add it to your cart, or contact us for a delivered quote.

In the box

• Mercury 6 HP 6MLH 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 by courier or freight, securely packed, dry and tracked. We’ll explain import duty and taxes for your country before you pay.

Buying from us

Read our refund and return policy, see our customer reviews, and visit the about page.

Mercury 6 HP 6MLH outboard motor FAQ

What shaft length is the Mercury 6 HP 6MLH outboard motor?

20 inches, long shaft.

Does it have reverse?

Yes, forward, neutral and reverse.

How heavy is it?

About 58 pounds.

Does it charge a battery?

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

Is it new?

Yes, with the full Mercury factory warranty.

Do you ship worldwide?

Yes. Contact us for a delivered quote.

Order your Mercury 6 HP 6MLH outboard motor

The strongest long shaft motor in Mercury’s lightweight range, with real reverse and its own fuel tank. Add the Mercury 6 HP 6MLH outboard motor to your cart, or ask us a question. You can also browse all our outboard motors for sale.