Yamaha F50AET Troubleshooting
| Engine Model: Yamaha F50AET |
| Engine Type: 4-stroke inline 4-cylinder OHC 8-valve gasoline outboard engine |
| Total Displacement: 57.1 cu.in (935 cc) |
| Rated Engine Power: 50 Hp (36.8 kW) at 5500 rpm |
| Fuel System: Carburetors |
____________________________________________________________________________________
| Engine starts hard or will not start |
No fuel in fuel tank - Add gasoline.
Improper fuel grade - Change fuel.
Fuel system clogged - Repair or replace.
Defective wiring connection of spark plug - Inspect the spark plug wire connection, replace or repair.
Spark plug is defective - Replace spark plug.
Clogged fuel filter - Fuel filter needs to be replaced.
Carburetor problems - Carburetor diagnostics required.
Fuel lines are clogged - Fuel lines must be clean.
Closed or clogged fuel tank air vent - Open or clean air vent.
Faulty fuel pump - Replace or repair fuel pump.
Throttle cable is damaged or adjusted incorrectly - Adjust correctly or replace the cable.
Excessive valve clearance - Need to adjust valve clearance.
Valve timing is wrong - Set the valve timing properly.
| Engine starts but then stops |
Damaged spark plug - Change spark plug.
Defective or clogged carburetor - Clean or replace carburetor.
Faulty ignition coil - Install a new ignition coil.
Closed or restricted fuel tank air vent - Fuel tank air vent need to be opened or cleaned.
Faulty fuel pump - Change or rebuild fuel pump.
Choke system malfunction - Change choke system components as required.
Improper valve clearance - Adjust valve clearance according to specifications.
Valve timing is incorrect - Adjust valve timing correctly.
Worn or loose valve springs - Valve springs need to be changed.
Stuck valves - Clean the valves.
Defective ignition - Test ignition and replace failed parts.
Fuel pump is damaged or dirty - Clean or install new fuel pump.
Carburetor not adjusted - Adjust according to instructions.
Restricted fuel lines - Clean fuel lines.
Closed or clogged fuel tank air vent - Open or clean air vent.
Fuel filter is plugged - Fuel filter needs to be replaced.
Gaskets are defective - Replace gaskets.
Water intake is blocked - Need to clean or wash.
Choke system malfunction - Check and repair choke system.
Engine overload - Reduce engine load.
Too lean fuel mixture in carburetor - Set the carburetor correctly.
Bad ignition timing - Adjust ignition timing correctly.
Faulty thermostat - Replace thermostat.
Water pump malfunction - Change water pump as required.
Incorrect propeller selection - Replace propeller.
Damaged or bent propeller - Replace propeller.
Outboard motor is mounted too high or too low - Mount the motor as required.
Engine oil level low - Add oil to the engine crankcase.
Oil pump is defective - Install new oil pump.
Water intake screen is dirty - Wash or clean as required.
Incorrect valve setting - Set the valves properly.
Stale gasoline - Use correct gasoline.
Engine is overloaded - Load reducing is recommended.
Incorrect low idle setting - Correct idle adjustment.
Fuel pump is faulty or clogged - Clean or change fuel pump.
Main bearings or crankshaft are worn out - Have bearings or crankshaft replaced.
Worn cylinder bore or piston rings - Change defective components.
Carburetor is improperly adjusted or clogged - Adjust the carburetor correctly or clean it.
Fuel pump is dirty or defective - Inspect fuel pump and change as required.
Defective ignition system - Check ignition system and replace faulty parts.
Worn cylinder head gasket - Install new head gasket.
Faulty powerhead parts - Defective components need to be replaced.
Valves are burned or stuck - Clean or replace valves.
Improper propeller diameter or pitch - Replace propeller.
Damaged or bent propeller - Have propeller repaired or replaced.
Outboard motor mounting height is set incorrectly - Have motor adjusted to proper transom height.
Improper trim angle - Adjust trim angle.
| Engine uses too much fuel |
Carburetor main jet adjustment is improper - Adjust it properly.
Defective or loose spark plug - Tighten or change the spark plug.
Piston, sleeve, or rings are damaged - Replace defective parts as required.
| Excessive engine vibration |
Damaged or bent propeller - Replace propeller.
Propeller shaft damaged - Replace propeller shaft.
Weeds wraped around propeller - Clean the propeller.
Engine mounting bolt is not tightened - Tighten the bolt as required.
Steering pivot is faulty or loose Tighten correctly or replace.
Low battery capacity - Low battery charging, charge as required.
Battery does not hold charge - Battery needs service or replacement.
Faulty battery terminals or disconnected cables - Check battery wires and service or replace terminals.
Faulty starter motor - Replace or repair starter.
| Trim motor is running but trim system cannot move up or down |
Oil level low - Checking oil level and add if necessary.
Pump assembly is defective - Check pump and replace if necessary.
Manual release valve leaking - Valve need to be closed or changed.
Motor or pump driveshaft faulty - Replace worn component.
| Trim does not fully up or down |
Pump assembly faulty - Replace pump.
Tilt ram piston ball is displaced - Clean or repair.
Tilt ram piston O-ring damaged - Change O-ring.
Low oil level - Checking oil level and add if necessary.
Lower check valve is not properly secured in port side trim ram - Install valve correctly.
____________________________________________________________________________________
| Outboard Engines Technical Specifications |
| Small Engines Technical Specifications |
| Car Engines Technical Specifications |
| Industrial Engines Technical Specifications |
