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| Home / Outboard Engines / Suzuki Engines / Suzuki DF9.9BS |
Suzuki DF9.9BS Troubleshooting
The Suzuki DF9.9BS 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 9.9 hp (7.3 kW) at 4700-5700 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 starts hard |
Empty gas tank - Add fuel.
Improper fuel grade - Change fuel.
There is air in the fuel system - Bleed the system.
Defective wiring connection of spark plug - Check the spark plug wire connection, repair or replace.
Spark plug is faulty - Change spark plug as required.
Clogged fuel filter - Replace or clean fuel filter.
Vapor separator needle valve is damaged or worn - Change vapor separator needle valve.
Clogged fuel lines - Clean fuel system lines.
Closed or restricted fuel tank air vent - Open or service air vent.
Fuel feed pump failure - Repair or change fuel feed pump.
Worn or improperly adjusted choke cable - Adjust properly or change the cable.
Valve clearance is wrong - Adjustment procedure required.
Valve timing is wrong - Set the valve timing correctly.
Low fuel pressure - Inspect fuel system for leaks or inspect low pressure fuel pump.
Clogged or worn fuel injector - Clean or install new injector.
Fuel regulator is faulty - Replace fuel regulator.
ECM is not functioning - Replace ECM.
| Engine starts and then stalls |
Spark plug is defective - Replace spark plug.
Vapor separator needle valve is bend or wear - Install new needle valve.
Ignition coil is not working - Install a new ignition coil.
Fuel tank air vent restricted or closed - Open or service air vent.
Fuel pump defective - Replace or rebuild fuel pump.
Damaged choke system - Change choke system components as required.
Improper valve clearance - Need to adjust valve clearance.
Valve timing is improper - Set the valve timing correctly.
Worn or loose valve springs - Change valve springs.
Stuck valves - Valves must be cleaned.
Bad cylinder compression - Check and replace worn parts.
Fuel filter is plugged - Fuel filter needs to be replaced.
Dirty or faulty fuel injector - Clean or install new injector.
Not enough engine oil - Check and refill engine oil.
Faulty oil pump - Change oil pump.
Water intake screen is dirty - Need to clean or wash.
Thermostat failure - Replace thermostat.
Defective water pump - Water pump need to be replaced.
| Unstable engine running |
Ignition system malfunction - Check ignition and replace faulty components.
Dirty or faulty fuel pump - Check fuel pump and change if required.
Worn or damaged vapor separator needle valve - Replace needle valve.
Fuel lines clogging - Clean fuel system lines.
Fuel tank air vent restricted or closed - Open or service air vent.
Fuel filter is clogged - Replace fuel filter.
Intake manifold air leaks - Change intake manifold gasket.
Clogged water intake - Wash or clean as required.
Throttle link and throttle valve are wear or damaged - Replace faulty components.
Fuel injector is faulty or clogged - Replace or clean if necessary.
| Engine overheating |
Engine overload - Load reducing is recommended.
Fuel injector or fuel pump is clogged - Replace or clean if necessary.
Ignition timing is wrong - Ignition timing needs to be set properly.
Thermostat is faulty - Thermostat need to be replaced.
Damaged water pump - Water pump need to be replaced.
Propeller selection improperly - Check the propeller size.
Damaged or bent propeller - Replace propeller.
Outboard motor is mounted too high or too low - Position the engine correctly.
Low engine oil level - Check and refill engine oil.
Oil pump failure - Install new oil pump.
Dirty water intake screen - Need to wash or clean.
Wrong valve setting - Adjust valves as required.
| Engine knocking sound or abnormal noise |
Stale or low octane fuel - Change fuel.
Excessive engine load - Reduce engine load.
Low idle speed setting is not correct - Adjustment required.
Fuel pump is damaged or dirty - Clean or install new fuel pump.
Main bearings or crankshaft are worn out - Repair or replace defective parts.
Worn cylinder bore or piston rings - Replace defective parts.
| Loss of engine power |
Dirty fuel lines - Fuel lines need to be cleaned.
Fuel injector is fault - Change fuel injector.
Fuel pump is dirty or defective - Inspect fuel pump and change as required.
Defective ignition - Check ignition and replace faulty components.
Worn cylinder head gasket - Replace the gasket as required.
Powerhead components are damaged - Change defective components.
Burned or stuck valves - Service or replace valves.
Propeller pitch or diameter incorrect - Install correct propeller.
Propeller bent or damaged - Have propeller repaired or replaced.
Incorrect outboard motor mounting height - Check the outboard motor mounting height.
Improper trim angle - Adjust trim angle correctly.
| Excessive fuel consumption |
Damaged or clogged fuel injector - Replace or clean as required.
Spark plug is loose or defective - Re-tighten or replace spark plug.
Worn sleeve, piston, or rings - Replace defective components as required.
ECU is not functioning - Change electronic control unit.
| Excessive motor vibration |
Propeller bent or damaged - Have propeller repaired or replaced.
Propeller shaft malfunction - Have propeller shaft replaced.
Weeds wraped around propeller - Remove weeds from propeller.
Motor mounting bolt is loose - Tighten bolt.
Steering pivot is loose or damaged Tighten correctly or replace.
| Starter will not work |
Battery capacity is low - Charge the battery.
Battery runs out quickly - Battery needs service or replacement.
Disconnected cables or faulty battery terminals - Check cables and clean or change terminals.
Starter motor failure - Starter should be changed.
| Trim motor runs but trim system does not move up or down |
Oil insufficient - Check and refill oil.
Damaged pump assembly - Test pump and replace if necessary.
Manual shut-off valve leaks - Close the valve or change it.
Broken motor or pump driveshaft - Change worn component.
| Trim does not fully up or down |
Pump assembly is faulty - Change pump as required.
Tilt ram piston ball is displaced - Service or repair.
Tilt ram piston O-ring damaged - Install new O-ring.
Low oil level - Fill up oil to required level.
Lower check valve is not properly secured in port side trim ram - Secure valve properly.
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