The following notes cover most aspects of trouble-shooting and while being fairly comprehensive they may not apply to every particular motor. They are nonetheless valid for most engines and should prove useful as a step-by-step guide which is intended to remind you what to look for — especially when you are working under stress.
Starter rope pulls out but engine does not turn over
1. Pawls bent or distorted.
2. Friction spring bent.
3. Too much grease on pawls and / or spring.
Rope pulls out but does not return
1. Recoil spring broken or sticking
2. Bent starter housing.
Recoil starter ‘clatters’
1. Starter spindle needs lubricating.
2. Friction spring bent.
3. Bent starter housing.
4. Too much grease on pawls etc
Electric starter will not operate
1. Battery discharged, or terminals corroded
2. Starter switch faulty
3. Corroded or faulty connections
4. Starter solenoid faulty
5. Starter motor wet.
6. Safety-switch open or faulty.
7. Throttle open too far.
Solenoid clicks but motor fails to turn
1. Poor connections.
2. Battery nearly flat.
3. Solenoid defective.
4. Pinion jammed.
Engine fails to start or is hard to start
1. No fuel. Tap turned off.
2. Fuel line blocked or kinked.
3. Engine not primed.
4. Tank vent closed.
5. Dirty fuel; choked filters.
6. Engine needs choke—throttle closed / wide Open.
7. Carb maladjusted — mix too lean.
8. Timing out.
9. Spark plug fouled, wrongly gapped.
10. Plug leads defective.
11. Points fouled, wrongly gapped.
12. Magneto wet and shorting.
13. Weak condenser / coil / broken wire.
14. Defective wiring,
15. Reed valve stuck shut or not seating.
16. Loose fuel connection.
17. Blocked jets / sunk float.
Engine overheats
1. Water intake blocked / restricted / outlet blocked.
2. Water pump defective.
3. Motor running too shallow.
4. Timing out.
5. Petroil ratio wrong.
6. Lower unit lacks oil / bent.
7. Propeller too small.
Engine misses at low revs
1. Petroil ratio wrong
2. Carb maladjusted.
3. Timing out.
4. Weak condenser / coil / broken wire.
5. Points fouled, wrongly gapped.
6. Spark plugs fouling / wrongly gapped.
7. Magneto-plate loose.
8. Reed valve malfunctioning.
9. Tank vent blocked.
10. Fuel contaminated.
11. Crankcase vent blocked.
Engine misses at high revs
1. Spark plugs fouled / wrongly gapped / wrong heat range
2. Points fouled / wrongly gapped.
3. Insulation breakdown / broken wire.
4. Weak condenser / coil.
5. Timing incorrect.
6. Carb out of adjustment.
7. Contaminated fuel.
8. Engine needs decoke.
9. Leaking head or exhaust gaskets.
Engine vibrates
1. Transom clamps loose.
2. Petroil ratio wrong.
3. Carb maladjusted – too rich.
4. Propeller fouled / broken.
5. Engine mount broken.
6. Ignition faulty.
7. Engine breathing exhaust fumes.
8. Fuel contaminated.
Engine runs, idles, then stops
1. Fuel filters fouled.
2. Tank vent closed.
3. Rope / weed around prop’.
4. Cooling water intake blocked / pump defective.
5. Petroil ratio wrong.
6. Carb maladjusted – slow speed adjustment.
7. Engine needs decoke / plugs fouling.
8. Spark plugs in wrong heat range.
9. Prop drive bent / needs lubricating.
Engine lacks acceleration, top revs low
1. Spark plugs fouled / wrongly gapped.
2. Points fouled / maladjusted.
3. Timing out,
4. Carb maladjusted.
5. Condenser / coil weak.
6. Reed valves defective.
7. Petroil ratio wrong.
8. Wrong propeller / fouled.
9. Lower unit lacks oil / bent.
10. Magneto-plate sticking.
11. Head or exhaust gasket blown.
Engine knocks
1. Petroil ratio wrong.
2. Bearings worn / pistons worn / etc.
3. Timing out—too advanced.
4. Engine needs decoke.
5. Flywheel loose / not centred.
6. Something loose.
Engine seizes
1. Petrol lacks oil.
2. Water pump defective / intake-outlet blocked.
3. Lower unit lacks oil / bent.
4. Broken crankshaft/con rod.
5. Piston seized.
First Aid For A Drowned Motor
Sooner or later an outboard gets dunked and the prudent w owner will have limited his chances of a total loss by using a lanyard or safety-chain to keep the outboard united with the boat. The very worst case is when the engine enters the water running flat out. Chances are then that it will cause itself severe mechanical damage as it tries to compress that virtually incompressible liquid — water. Even in this case what you do next may minimise the repair charges.
The real danger to the engine — assuming it has suffered no mechanical damage — lies in the fact that salt water is corrosive — especially with raw aluminium. And even if your boat inland, consider that bright coloured effluent you are floating in also contains harmful substances.
Speed is essential. Strip off the cowl and wash off with fresh water any mud, sand etc. Remove sparkplugs and carburettor and turn motor over by hand to expel water from the powerhead. Dry magneto, plug and leads, and spray with de-wetting fluid (WD 40 and all that). If you have any meths aboard pour some into bore and crankcase and swill around engine, and drain – this spirit (alcohol) will combine with any water present and hasten its removal. Strip and clean the carb, pump and fuel lines, re-prime with fresh petroil. Oil bore and turn engine over slowly to help coat all surfaces. Inspect cooling system for mud, sand or weed — especially around inlet. Re-assemble engine, start, and run for at least twenty minutes. If engine refuses to start then chances are the magneto coils have shorted. Do not attempt to dry in oven, a warm place in the sun wilt provide the gentle heat needed.
Even if you successfully get the engine to run it should really be returned to your dealer for a complete service. Water — especially salt — will cause corrosion damage to the engine’s precision parts such as main bearings and crankshaft journals.
What if you are unable to attempt to get the engine started, or the engine has been submerged for some time before you could recover it?
Corrosion attack really needs the presence of air to get it going and this means that damage may be reduced, or even prevented, if the engine is kept in a waterbath. This may seem drastic but even a saltwater bath is preferable to letting the engine start to dry out. Of course fresh water is first choice and most engines will fit into a large-gauge plastic bag. Prompt action may limit your subsequent bills!
Remember
• Never get the powerhead lower than the propeller— water could drain back into the crankcase and cylinder.
• Always disconnect the battery when leaving the boat for long periods — a ‘leak’ may promote electrolytic corrosion or flatten the battery.
• Never get oil on the contact breaker points — this will cause arcing and fouling and make the motor run ragged. Check adjacent oil seals.
• Always use the correct fuel/oil mix. Excessive quantities of oil will cause the spark plugs to foul and the engine run ragged or refuse to start. Too little will cause engine wear.
• Never run the engine with a damaged propeller —an out-of-balance prop’ will make the engine vibrate and cause substantial wear to the shaft.
• Always use the highest numbered (hottest) sparkplug — low numbered (cooler) plugs tend to foul and affect the smooth operation of the motor.
• Never run the engine out of water — it will overheat and possibly wreck the waterpump impeller which needs water lubrication.
• Always disconnect the battery when working on the electric starter — this will prevent shocks and also eliminate the risk of the motor accidentally starting.
• Never use detergent based oils or fuel additives—these will adversely affect engine performance and could invalidate warranties and guarantees.
• Always disconnect and earth spark plug leads when working on the manual starter—this will prevent shocks and the engine accidentally starting.
SPARES
Recommending a comprehensive list of essential spares for an outboard is difficult—so much depends upon the particular make and model in question. However, certain things should be carried and the following list is a starting off point to which specific items may be added (or deleted) as required.
• Two spark plugs for each cylinder—cleaned and correctly gapped.
• Can petroil — replace contents periodically.
• Shear pins or spare propeller if rubber bushed.
• Propeller split pins (or tab washers).
• Spare starter cord.
• Spanners, including special plug spanner
• Feeler gauges.
• Non-linting rag.
• Plug lead(s)
• Magneto points
• Condenser
• Distributor rotor
• Distributor cap
• Coil.
• Fuel pump reservicing kit and filters.
• Carb reservicing kit – (jets, gaskets etc.)
• Waterpump impeller / key.
• Touch-up paint
• De-wetting aerosol
• Grease
• Oil.
• Handbook.