Outboard Motor Repair

Who it is for. Beginners with no formal certificate, including school leavers, young fishers, women's groups and persons with disabilities. National Proficiency I is the first level of Ghana's TVET framework.

Why outboard repair

• In 2023 the Canoe and Fishing Gear Owners Association of Ghana (CaFGOAG) reported more than 30 cases of faulty outboard motors at sea in the Volta, Greater Accra, Central and Western regions after fishing resumed on 1 August 2023. It blamed poor maintenance and advised servicing at least every six months and repairing small faults while the motor still runs.
• Many coastal communities received subsidised outboard motors, so there are many motors to look after.
• Drowning is the leading cause of death among small-scale fishers. A motor that is looked after and a crew that wears lifejackets save lives.

How the module works

Each unit has learning outcomes, performance criteria, the range and the evidence your assessor needs. You are judged Competent or Not Yet Competent. About 70% of the time is practical.

Every unit has a practical task, homework and a short Check yourself quiz.

Competency standard

Range. The training workshop and a launch point. Evidence. Safety checklist; oral questions; observation.

Fuel and fire

Petrol and its vapour burn easily and can explode.

Opening a portable tank. Sun heat builds pressure inside. Open the air-vent screw fully first to let the pressure out, then open the cap slowly, or fuel can spray out. When you carry the tank, close both the cap and the vent screw, or vapour leaks out of the vent.

Hot engine. Never work on the fuel system while the engine is running or still hot. Do not touch spark plugs right after stopping, and do not drain engine oil when it is hot.

Old fuel. Throw away old or dirty fuel the way local rules say. The Ghana rule for disposal was not verified; ask the Assembly or the dealer, and never pour fuel into drains or the sea.

The propeller and accidental starting

An engine that starts by accident can cut you badly. Before you touch the propeller, or before you flush the engine, do all of these:

1. Remove the stop-switch lock or lanyard key.
2. Pull the spark plug caps off.
3. Put the gear in neutral.
4. Turn the main switch off, and disconnect the battery if there is one.

• Propeller edges are thin and sharp; wear gloves when you change a propeller.
• A person in the water cannot dodge a moving boat, even at low speed. Shift to neutral and stop the engine when you are near people in the water.
• Never work under a motor that is tilted up and held only by its lock. Lock the tilt stopper and secure the motor to the transom or a stand before you do gear-oil work.
• Do not run the engine with the propeller on when you flush it with a hose or in a test tank. Take the propeller off first.

The emergency stop switch and lanyard

The lanyard is a cord from the stop switch to the driver. If the driver falls overboard, the cord pulls out and the engine stops. It is the driver's job to wear it. Honda says the same. Never tie the stop switch down to bypass it.

Carbon monoxide

Exhaust gas contains carbon monoxide. You cannot see or smell it, and it can kill. Never run an engine in a closed workshop or a covered boat shed, and stand on the windward side.

Lifejackets and drowning

• The driver and passengers are responsible for wearing lifejackets.
• WHO says more than 80 fishers die every day while fishing; drowning is the main cause, few fishers wear lifejackets and many carry no safety equipment.
• In Ghana, the Ghana Maritime Authority said in August 2026 that it was processing a rule to make lifejackets compulsory on inland waters. It reported 9 boat accidents and 42 deaths between 2024 and June 2026, and a programme that sold 20,000 lifejackets at a subsidised GH¢250 each. We did not find a rule for canoes at sea, so wear one anyway.
• Wearing the lifejacket before the canoe leaves the beach is the rule in this course.

Noise and lifting

• A 25 or 30 hp four-stroke measured about 79 dB(A) at the driver; a 40 or 50 hp two-stroke measured about 91 dB(A). That is 12 dB(A) louder, so the two-stroke is much louder. Wear ear protection when you test-run engines (general practice, not verified).
• A 25-30 hp outboard weighs about 72-87 kg depending on type. Mounting needs enough people or a hoist; do not lift alone.

Safety gates in this course

Check yourself

1. Which do you open first on a portable fuel tank, the vent screw or the cap?
2. Name the four things you do before touching the propeller.
3. What does the lanyard do?

Competency standard

Range. One two-stroke and one four-stroke engine. Evidence. Labelled parts sheet; tool check; oral questions.

The main parts

Walk round the engine with your hand, from top to bottom.

Two-stroke or four-stroke?

Model codes. The letters in the engine's name tell you things. In the Tohatsu example F30CEPTL means four-stroke, 30 hp, C generation, electric start, remote steering, power trim and tilt, long shaft. Other makers use different codes: read the plate and the manual.

Find your model. On a real engine, write down the make, model, horsepower and serial number from the plate. You need these to ask for parts and for the right manual.

Basic tools

The tool bag Tohatsu supplies is a good minimum kit: a 16 mm spark plug socket and handle, a 10-13 mm socket, pliers, a screwdriver, a spare spark plug, a spare split pin for the propeller nut, a spare stop-switch lock, an emergency starter rope and a flushing attachment.

Where to buy. Ask at a marine or motor-spares shop in Takoradi, Sekondi or Accra, or at a dealer for your make. We did not find shop names or prices, so we do not give any; see the price survey homework. Yamaha's agent in Ghana is Japan Motors Trading Co, with a Takoradi branch, but whether it stocks outboard parts was not verified. For any engine, ask the maker's dealer for the manual and genuine parts.

Tool rules

Check yourself

1. What is the difference in oil between a two-stroke and a four-stroke?
2. What does the tell-tale show?
3. Why does the propeller nut need a split pin?

Competency standard

Range. A two-stroke engine; a four-stroke for comparison. Evidence. Mixing calculations; a mixed batch; oral questions.

Step 1: find the maker's ratio

The mixing ratio says how many parts of petrol to one part of oil. A ratio of 50:1 means 50 parts petrol to 1 part oil.

Do not guess. Read your engine's manual or the label under the cowl. If you do not have either, ask the dealer. We did not find a reliable source for the Yamaha, Suzuki or Mercury ratio, so this book does not state one. Online forums disagree.

Example only, from the Tohatsu M40D2 manual: after break-in, use 50:1; during break-in of a new engine, use 25:1. The oil must be genuine two-stroke oil or NMMA-certified TC-W3 outboard oil. Oil-injected (auto-mix) engines mix by themselves, so you do not pre-mix for those, except that the same manual still asks for 50:1 pre-mix during break-in. Read your own manual.

Step 2: work out the oil

The rule is:

litres of petrol × 1000 ÷ ratio = millilitres (mL) of oil

For 50:1, every litre of petrol needs 1000 ÷ 50 = 20 mL of oil. For 25:1, every litre needs 1000 ÷ 25 = 40 mL.

The 12 litre and 25 litre rows at 50:1 match the Tohatsu calculator. The other rows are worked out here with the rule above.

A percentage way to think. 50:1 is the same as 2% oil, and 25:1 is 4% oil. So 20 litres at 2% is 400 mL.

Step 3: mix it, safely

1. Do it outdoors, away from flame, with the engine off.
2. Use a clean, approved fuel container with a good cap. Know its size.
3. Measure the oil with a clean measuring jug that is only for oil. Do not guess by eye.
4. Pour the oil into the tank first, then the petrol.
5. Close the cap tightly and close the air-vent plug.
6. Shake well.
7. Write on the container with a marker: the date, the ratio and "PREMIX". Never leave a mixed container unmarked.
8. If the boat has a built-in tank, mix in a separate container and pour it in.
9. Wipe up any spill and wash your hands.

Steps 4 to 8 follow the Tohatsu method.

Mistakes and fixes. Poured petrol first and the oil sits at the bottom: shake longer. Forgot to write the ratio: do not use it; ask the person who mixed it, or throw it away properly. Unsure whether oil is already in the fuel: do not add more; ask first.

Ghana premix fuel

Premix is subsidised fuel for artisanal fishing outboards, sold through landing beach committees. From 1 September 2026 the official price was GH¢5.51 per litre and GH¢24.80 per gallon. The earlier price in May 2026 was GH¢5.60 per litre and GH¢25.20 per gallon. A beach committee charging above the approved price can be punished. Prices change, so ask the beach committee for today's price.

How big is a Ghana gallon? Divide the gallon price by the litre price: 24.80 ÷ 5.51 is about 4.5 litres. This is worked out from the two prices and is not stated in a source, so check your own container.

Does premix already have oil in it? We did not verify the official oil ratio in premix. Ask the beach committee and the dealer, and read your engine's manual. A four-stroke must not run on premix (the reason is in Unit 2). Never pour oil into a tank before you know what is already in it.

Pump petrol and diesel mixes. Reports say some fishers buy pump petrol and diesel and mix them when premix runs short. Diesel does not belong in an outboard; do not copy this.

Fuel quality

• Four-strokes: use only fuel with up to 10% ethanol, no more. Ethanol in Ghana petrol was not verified; ask the filling station.
• Ethanol fuel attracts water. Look for water in the see-through filter cup, and squeeze the primer bulb before starting: if it does not firm up, look for a leak.
• Old petrol goes bad. Honda says it can start to go off in as little as 15 days. Do not fill your tank for months ahead.
• Check fuel hoses before every trip: look, and smell for fuel.

Check yourself

1. What does 50:1 mean?
2. How much oil goes into 20 litres of petrol at 50:1?
3. Why do you never use car oil in a two-stroke outboard?

Competency standard

Range. One engine. Evidence. Completed service sheet; observed tasks.

How often?

The maker sets the intervals in the manual. Two examples:

• Tohatsu M40D2 two-stroke: check the plugs and gear oil at 10 hours or 1 month, 50 hours or 3 months, 100 hours or 6 months; replace the water-pump impeller every 12 months; the carburettor strip and clean is a dealer job.
• Tohatsu MFS25C/30C four-stroke: first service at 20 hours or 1 month, then every 50 h or 3 months, 100 h or 6 months, 200 h or 1 year, whichever comes first.
• CaFGOAG advised servicing at least every six months. Honda says to service more often in salt water and to keep a log of engine hours.

The daily check before every trip

Job 1: the spark plug

Tools: plug spanner, feeler gauge, torque wrench if you have one, gloves. New plug of the exact type in your manual.

1. Stop the engine and let it cool. Remove the stop-switch lock.
2. Remove the top cowl. Pull the plug caps off, by the cap, not by the wire.
3. Unscrew the plug with the plug spanner.
4. Look at it. Replace it if the electrode is worn, or if the white insulator is cracked or chipped. Never reuse a plug with damaged insulation.
5. Measure the gap with a wire-type feeler gauge. Example gaps: 0.8-0.9 mm on the Tohatsu four-stroke, 0.9-1.0 mm on the M40D2, 0.6-0.7 mm on the Honda BF40D. Use your manual's figure.
6. If the gap is wrong, fit a new plug, or clean and re-gap a reusable one.
7. Screw the plug in by hand first so it does not cross-thread.
8. Tighten. Example torque is 18 Nm; if you have no torque wrench, tighten 1/4 to 1/2 turn past finger-tight, and check with a torque wrench as soon as you can.
9. Push the cap on firmly.

Reading a plug. Plug colour tells a story: black and sooty, oily, or very white. General practice (not verified): ask your trainer to show you plug photos from your own engines and talk about what each means.

Mistakes and fixes. Cross-threaded plug: stop and ask. Wrong plug type: the engine may run badly or be harmed; check the part number. Plug cap loose: engine misfires; push it on until it clicks.

Job 2: the fuel filter cup

Engine cool, no flames nearby, work outdoors.

1. Look at the cup: is there water or dirt?
2. If the filter is the type that opens, disconnect the hoses and remove the cup, filter and O-rings.
3. Look for wear and blocking. Replace parts if needed.
4. Empty fuel, water and dirt into a container, then dispose of it properly.
5. Refit everything, including the O-rings. A missing part can cause a leak, a fire or an explosion. The arrow on the filter shows the direction of flow.
6. Squeeze the primer bulb, check for leaks, and wipe any fuel.

Yamaha says a sealed spin-on filter should be replaced, not drained and refitted. Follow your engine's manual.

Job 3: gear oil

Gear oil lubricates the gears in the gear case. Example: Tohatsu M40D2 uses API GL-5, SAE 80-90, 500 mL; the Tohatsu four-stroke uses GL-5, SAE 80-90, about 360 mL. Honda lists different grades and amounts, and its sheet gives GL-4 or GL-5 for different models. Use your manual's grade and amount.

1. Stop the engine. Make the engine safe (Unit 1). The motor must be upright and firmly held.
2. Put a clean tray under the gear case.
3. Remove the drain bolt first (lower), then the level bolt (upper).
4. Let the oil run out.
5. Look at the oil. Milky = water has got in. Black and burnt-smelling = a fault. Either way, tell your trainer and have the engine checked. Do not just refill and go.
6. Wipe the magnetic end of the drain plug: very fine metal dust is acceptable, metal chips are not.
7. Pump new oil in through the bottom (drain) hole until it comes out of the level hole with no bubbles.
8. Fit the level bolt, take out the pump, and quickly fit the drain bolt. Use new sealing washers every time.
9. Wipe the gear case clean. Put the old oil in a sealed container for recycling. We did not find a used-oil collection point for the Western Region; ask the Assembly or a workshop.

Job 4: the propeller and split pin

1. Make the engine safe: remove the stop-switch lock and plug caps, shift to neutral.
2. Put a wooden block between a blade and the anti-ventilation plate to hold the propeller still.
3. Remove the split pin, then the nut and washer.
4. Pull the propeller and the thrust holder off the shaft.
5. Look at the blades: bent or chipped blades lose power and can harm the engine.
6. Clean the shaft and grease it with waterproof grease.
7. Refit the thrust holder, propeller, washer and nut. Never fit a propeller without its thrust holder.
8. Tighten the nut (example 25 Nm on the Tohatsu four-stroke).
9. Line up a groove in the nut with the hole in the shaft. Fit a new split pin and bend its legs apart. Never reuse a split pin.

Shear pin. Some small outboards use a small shear pin through the propeller hub that breaks on impact to protect the shaft and gears. We did not find the replacement steps in any manual we read. Trainer to check: teach it from the learner's own engine manual and keep a spare pin in the bag.

After you hit something. If you strike an underwater object, stop the engine at once, check the controls, the gear case and the transom, return slowly, and have the motor checked.

Job 5: the anode

The anode is a metal piece that rusts away so the engine does not. Replace it when it has eroded to less than about two-thirds of its original size. Never grease or paint it. Tighten the anode bolt at each inspection. Honda says the same about painting.

Job 6: the water pump impeller (know about it)

The impeller is a rubber wheel that pumps cooling water. It wears, and rubber also goes hard with age. Tohatsu says to inspect it each year and replace it at least yearly, depending on use. Never run the engine without water, because the impeller can burn up in seconds.

Trainer to check. Replacing the impeller means taking the lower unit off, which the free manuals call a dealer job. At Level 1, learn the signs of a bad impeller (overheating, weak tell-tale stream) and do not take the lower unit apart without a trainer and the engine's workshop manual. These steps are taught in Level 2.

Keep a service record

Write the date, engine hours (if there is a meter) or trip count, and what you did in a service record. Honda advises commercial users to log hours so they can set their own intervals.

Check yourself

1. Which gear-oil bolt do you remove first?
2. What does milky gear oil mean?
3. Why must a split pin never be used twice?

Competency standard

Range. One engine; salt-water use. Evidence. Flushing record; storage sheet; observed tasks.

Flushing, step by step

After every use in salt, brackish or dirty water, flush with fresh water.

Two methods exist. Some makers flush through a port with the engine off; some flush with the engine running in a tank. Follow your own manual.

Method A: flush attachment with the engine off (Tohatsu example).

1. Remove the stop-switch lock. Tilt the motor down.
2. Take the flushing-connector cap off and screw on the flushing attachment.
3. Connect the hose and turn the water on.
4. Flush for 3 to 5 minutes with the engine not running. (Honda's flush port procedure says at least 10 minutes.)
5. Turn the water off, take the attachment off and refit the cap.
6. Tilt the motor up when dry.

Method B: test tank. Remove the propeller. The water must be at least 10 cm above the anti-ventilation plate. Some Yamaha guidance turns fresh water on before starting and off after stopping; only do that if your manual says so.

After flushing

• Wipe the exterior and touch up scratched paint.
• Coat rust-prone parts with a corrosion inhibitor; do not spray inhibitor or water on electrical parts under the cowl.
• Lubricate controls and linkages with silicone spray.
• Never grease or paint the anode.

Storage for a long rest (steps from the Tohatsu manuals)

1. Take off the plug caps and stop-switch lock; disconnect the battery.
2. Wash the outside; flush the cooling system and drain it.
3. Drain fuel from hoses, pump, filter and the carburettor (loosen the carburettor drain screw and tilt the motor up until fuel drains) or from the vapour separator.
4. Remove the plugs. Put about a teaspoon of engine oil or storage spray in each cylinder. With the stop-switch lock removed and a cloth over the plug holes, turn the engine over a few times.
5. Refit the plugs.
6. Change the engine oil (four-stroke) and gear oil.
7. Grease the grease points.
8. Store the motor upright in a dry place.
9. Batteries: store fully charged, dry, and recharge monthly.
10. Fuel stabiliser: add to a full tank of fresh fuel and run for about 10 minutes in water. Fuel left in a carburettor makes gum and varnish and sticks the float valve.

Moving or lying down

Drain the fuel and oil before laying a four-stroke down, and keep the power head 2 to 4 inches higher than the rest.

Back in use

Check the shift and throttle by turning the propeller shaft while shifting, check the battery, and change the oil. With the plugs out, crank the engine to prime the oil pump. After starting, warm up 3 minutes in neutral, 5 minutes slow, and 10 minutes at half throttle.

A motor that has been under water

Do not start it. Wash it with fresh water, drain the water and oil, take out the plugs and pull the starter to drain the cylinders, change the oil and filter, spray oil into the cylinders, and take it to a dealer.

New engine break-in

A new engine must be broken in in the water, under load, with the propeller fitted. The Tohatsu table runs from idle for the first minutes, through under half throttle, then three-quarter throttle for about 10 hours, to full throttle after 10 hours. Follow your manual.

Check yourself

1. How long does Tohatsu say to flush with the attachment, and must the engine run?
2. How is a motor stored for a long rest?
3. Why must the propeller be off when flushing in a test tank?

Competency standard

Range. One fault set on a training engine. Evidence. Fault-finding record; observed tasks.

The order of checking

For a hard-starting engine, think fuel, spark, air, water. The causes come from the Tohatsu manuals; the order is our teaching design (general practice, not verified).

Won't start or hard to start

Check, in this order:

1. Lanyard and stop-switch lock in place? Gear in neutral?
2. Fuel: Is there fuel in the tank? Is the air vent open? Is the fuel hose connected with the right connector? Squeeze the primer bulb until it is firm. A deformed or damaged hose, or air in the fuel line, can stop fuel.
3. Water in the filter cup? Dirt?
4. Wrong fuel or oil? Too much fuel (flooding)?
5. Spark plug: take it out, look at it (wet, dry, black?), check the gap, test for spark with your trainer.
6. Battery (electric start): about 12-13 V at rest on a multimeter; loose or corroded terminals.
7. Still not starting: carburettor, ignition timing, compression. Stop. This is a job for a trainer, a licensed mechanic or a dealer.

Overheating or no water from the tell-tale

1. Stop the engine at once and do not restart until fixed.
2. Clear the tell-tale hole with a thin wire or air.
3. Check the water intake on the gear case for sand, plastic or weed.
4. If the intake is clear, the impeller probably needs replacing, or something is blocking the lower unit. A thermostat can also be at fault. Tell your trainer.

Some engines beep and limit speed when water temperature is too high. Sand, salt and shell wear the impeller. The tell-tale and thermostat advice comes from the maker's FAQ and table.

Rough idle or runs then stops

Check the same fuel and spark causes as above. Then look at the propeller (bent or damaged), a broken recirculation pipe, the thermostat, the engine height on the transom and an unbalanced load. These come from the Tohatsu table.

No power, cannot reach full speed

Look for: a damaged or wrong propeller, a heavy load, the engine mounted too high or too low, a blocked fuel system or carburettor, low compression or overheating protection. The propeller must let the engine reach the rpm range on its plate. Checking rpm and changing the propeller are taught at Level 2.

Water in the fuel

Signs: starts, then dies or misfires; water visible in the filter cup.

1. Stop. Check the cup and filters.
2. Drain the fuel from the carburettor or vapour separator until what comes out has no water or dirt; refill and drain again if needed.
3. Clean the tank and tank filter, especially after storage over three months.
4. Replace a water-separating filter if you have one.
5. Find where the water came from: bad fuel, an open tank cap, rain, or condensation in a half-full tank.

Milky engine oil or milky gear oil: do not run the engine. See a dealer.

Fault record

Write what the engine did, what you checked, in what order, what you found and what you fixed. Use this simple table.

Check yourself

1. Name the first two things you check when an engine will not start.
2. What do you do when the tell-tale shows no water?
3. Name one job you must leave to a licensed mechanic or dealer.

Competency standard

Range. The trainee's own plan. Evidence. One-page plan; price list.

Where to work

Ask the chief fisherman and the canoe owners' group (CaFGOAG branch) how many motors work at the site and who pays. We did not find those numbers.

Business ideas

Many motors need servicing, and CaFGOAG said minor faults should be fixed early and servicing done at least every six months. These are ideas, not sourced market facts:

• Mobile mechanic. Walk or ride to landing beaches with a tool bag, plugs, gear oil, fuel filters and primer bulbs.
• Service point at a landing site: flush, plug, gear oil, propeller check.
• Parts counter: plugs, oils, filters, split pins, nuts, lifejackets.
• Service plan for a group of canoe owners: every six months for a fixed fee agreed in advance.
• Safety talk and lifejacket sales with the beach committee.

Know your price

Prices were not found for parts or labour, so work them out yourself. Use your price survey from Unit 2.

Market yourself

• A clear name and a simple sign or sticker for the toolbox.
• Be on time. Explain the work before you start and show the old parts (the old plug and old gear oil) to the customer.
• Give a small written service record. Customers who see proof come back.
• Ask satisfied owners to tell the others at the beach.
• A short WhatsApp message with a photo of the finished service.
• Tell customers the truth when a fault is beyond your skill.

Accessibility

Under Ghana's Persons with Disability Act 2006 (Act 715), people with disabilities have rights to training and fair employment. Which tasks are workable (our suggestion, not sourced; confirm with learners with disabilities and an occupational therapist):

Give the safety rules in writing and with pictures, not only by voice. For a learner with a hearing impairment, agree hand signals before the engine runs.

Check yourself

1. Name two services a landing-site mechanic can sell.
2. What must you do before you start a job?
3. Why does this book tell you not to sell fuel or premix?

1. Which do you open first on a portable fuel tank, and why?
2. Name the four steps that make an engine safe to touch.
3. What does the lanyard do?
4. What is the difference between a two-stroke and a four-stroke in oil and fuel?
5. How much oil goes into 20 litres of petrol at 50:1?
6. Where do you find the right mixing ratio for your engine?
7. How do you know if a spark plug must be replaced?
8. Which gear-oil bolt do you remove first, and what does milky oil mean?
9. Why must you never reuse a split pin?
10. What must you do after use in salt water?
11. An engine will not start. What do you check first?
12. Name one job you must leave to a licensed mechanic or dealer.

Best next reads: your engine's owner's manual; the Tohatsu and Honda manuals listed below (free from the makers); and the Hub's Workplace Safety and Money Skills manuals.

What this module does not cover: Yamaha, Suzuki and Mercury engine specifics (use your own manual); impeller and lower-unit removal, carburettor cleaning, electrical testing and propeller selection (Level 2); running a workshop and accounting (Level 3).

Every source used in this manual is listed, with links, in the Teacher Copy.