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Suzuki DF20AS Troubleshooting
The Suzuki DF20AS is a four-stroke two-cylinder overhead cam gasoline short shaft outboard engine. This engine has a multi-point sequential electronic fuel injection, integral fuel pump, water cooled with thermostat, and capacitor discharge ignition system. A 20.1 cu.in (327 cc) outboard motor has a cylinder bore of 2.38" (60.4 mm), piston stroke of 2.24" (57 mm), and maximum power of 20 hp (14.7 kW) at 5300-6300 rpm. The boat motor is equipped with a manual or electric starting system, 3-blades aluminum standard propeller, manual or power trim and tilt, and tiller handle or remote control steering system. The fuel tank has a capacity of 3.2 gal (12 liters).
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| Engine doesn't start or difficult to start |
No fuel in fuel tank - Fill fuel up.
Incorrect fuel grade - Use quality fuel.
Dirty fuel system - Check and clean.
Spark plug wiring connection is damaged - Inspect spark plug wiring connection, change or repair.
Spark plug is faulty - Change spark plug as required.
Fuel filter is clogged - Fuel filter needs to be replaced.
Damaged or wear vapor separator needle valve - Change vapor separator needle valve.
Clogged fuel lines - Clean fuel system lines.
Closed or restricted fuel tank air vent - Fuel tank air vent need to be opened or cleaned.
Defective fuel feed pump - Fuel feed pump need to be replaced.
Worn or unadjusted choke cable - Change cable or adjust correctly.
Incorrect valve clearance - Adjust valve clearance.
Valve timing is incorrect - Set the valve timing properly.
Low fuel pressure - Check system for fuel leaks or check low pressure fuel pump.
Fuel injector is faulty or clogged - Replace or clean as required.
Fuel regulator failure - Change fuel regulator.
ECM is not functioning - Change electronic control modul.
| Engine starts but immediately shuts off |
Faulty spark plug - Install new spark plug.
Vapor separator needle valve is damaged or worn - Change vapor separator needle valve.
Damaged ignition coil - Install a new ignition coil.
Closed or restricted fuel tank air vent - Open or clean air vent.
Fuel pump defective - Change or rebuild fuel pump.
Choke system is damaged - Check and repair choke system.
Valve clearance is improper - Adjust to proper valve clearance.
Incorrect valve timing - Adjust valve timing as required.
Bad or broken valve springs - Install new valve springs.
Stuck valves - Valves need to be cleaned.
Low compression - Check and repair damaged parts.
Clogged fuel filter - Replace fuel filter.
Clogged or worn fuel injector - Replace or clean if necessary.
Engine oil level is low - Fill the crankcase with engine oil.
Defective oil pump - Replace oil pump.
Water intake is clogged - Need to wash or clean.
Thermostat is faulty - Replace thermostat.
Water pump failure - Change water pump.
| Unstable engine running |
Defective ignition - Check ignition system and replace faulty parts.
Fuel pump is faulty or clogged - Inspect fuel pump and change as required.
Worn or defective vapor separator needle valve - Install new needle valve.
Fuel lines are clogged - Clean fuel system lines.
Fuel tank air vent clogged or closed - Open or service air vent.
Plugged fuel filter - Fuel filter needs to be replaced.
Intake manifold air leaks - Replace intake manifold gasket.
Clogged water intake - Clean and wash as required.
Throttle valve and throttle link are defective or worn - Change faulty parts.
Fuel injector is faulty or clogged - Replace or clean if necessary.
| Engine keeps overheating |
Engine overloaded - Load reducing is recommended.
Clogged fuel pump or fuel injector - Replace or clean if necessary.
Ignition timing is wrong - Adjust ignition timing correctly.
Damaged thermostat - Install new thermostat.
Water pump failure - Change water pump.
Improper propeller diameter or pitch - Check the propeller size.
Damaged or bent propeller - Replace propeller.
Outboard motor is mounted too high or too low - Mount the motor as required.
Insufficient engine oil - Fill the crankcase with engine oil.
Oil pump malfunction - Change oil pump.
Water intake is clogged - Need to clean or wash.
Valve setting is improper - Adjust valves as required.
| Abnormal engine noise or knocking |
Stale or low octane fuel - Use correct fuel.
Engine overload - Load reducing is recommended.
Incorrect low idle setting - Adjust idling as required.
Clogged or defective fuel pump - Check fuel pump and replace if necessary.
Main bearings or crankshaft are worn out - Have bearings or crankshaft replaced.
Worn piston rings or cylinder bore - Change defective parts.
| Lack of engine power |
Fuel lines are dirty - Fuel lines need to be cleaned.
Defective fuel injector - Check fuel injector and change if required.
Fuel pump is clogged or faulty - Service or replace fuel pump.
Defective ignition system - Inspect ignition system and change failed components.
Defective cylinder head gasket - Replace the head gasket.
Faulty powerhead parts - Change defective parts.
Burned or stuck valves - Replace or service valves.
Propeller pitch or diameter incorrect - Install correct propeller.
Damaged or bent propeller - Replace propeller.
Outboard engine mounting height improperly - Check the outboard engine mounting height.
Incorrect trim angle - Make the correct trim angle adjustment.
| High fuel consumption |
Dirty or faulty fuel injector - Replace or clean as required.
Loose or defective spark plug - Change or re-tighten spark plug.
Worn rings, piston, or sleeve - Change defective components.
ECU is faulty - Change electronic control unit.
| Motor vibrates excessively |
Propeller bent or damaged - Replace propeller.
Damaged propeller shaft - Have propeller shaft replaced.
Weeds in the propeller - Remove and clean propeller.
Engine mounting bolt is not tightened - Tighten bolt.
Loose or faulty steering pivot Tighten or replace.
| Starter is not working |
Low battery voltage - Battery needs to be recharged.
Battery discharges quickly - Service charging system or replace battery.
Bad terminals or disconnected battery cables - Connect wiring properly or install new terminals.
Starter motor failure - Replace or repair starter.
| Trim motor is running but trim system cannot move up or down |
Oil level is insufficient - Checking oil level and add if necessary.
Pump assembly is faulty - Check pump and replace if necessary.
Leakage of manual release valve - Close the valve or change it.
Broken motor or pump driveshaft - Replace defective component.
| Trim cannot be fully up or down |
Pump assembly faulty - Change pump.
Tilt ram piston ball is not positioned correctly - Clean or repair.
Damaged tilt ram piston O-ring - Change O-ring.
Oil insufficient - Fill up oil.
Lower check valve not seating in port side trim ram - Install valve correctly.
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