Yamaha T50TLR Troubleshooting
| Engine Model: Yamaha T50TLR |
| 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 |
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| Engine starts up hard or won't start |
Fuel tank is empty - Fill fuel up.
Low-quality gasoline - Use correct gasoline grade.
Air in the fuel pipes - Bleed the fuel pipes.
Damaged spark plug wiring connection - Check the spark plug wire connection, repair or replace.
Defective spark plug - Install new spark plug.
Clogged fuel filter - Fuel filter needs changing.
Carburetor settings incorrect - Adjusting as required.
Clogged fuel lines - Clean fuel system lines.
Fuel tank air vent restricted or closed - Fuel tank air vent need to be opened or cleaned.
Fuel pump is faulty - Repair or change fuel pump.
Incorrectly adjusted or damaged throttle cable - Adjust correctly or change the cable.
Valve clearance is improper - Need to adjust valve clearance.
Valve timing is incorrect - Adjust valve timing correctly.
| Engine starts but then stalls |
Damaged spark plug - Spark plug need to be replaced.
Clogged or defective carburetor - Service or repair carburetor.
Ignition coil is damaged - Change ignition coil as required.
Fuel tank air vent restricted or closed - Fuel tank air vent need to be opened or cleaned.
Faulty fuel pump - Install new fuel pump or rebuild it.
Damaged choke system - Inspect and replace choke system components.
Excessive valve clearance - Adjust valve clearance.
Incorrect valve timing - Set the valve timing correctly.
Worn or loose valve springs - Replace valve springs.
Valves sticking - Clean the valves.
Ignition system problems - Check ignition system and replace faulty parts.
Clogged or defective fuel pump - Test fuel pump and replace if necessary.
Carburetor malfunction - Check and repair as required.
Clogged fuel lines - Service fuel lines.
Fuel tank air vent restricted or closed - Fuel tank air vent need to be opened or cleaned.
Fuel filter is clogged - Install new filter.
Damaged gaskets - Install new gaskets.
Water intake is blocked - Clean and wash as required.
Damaged choke system - Check and repair choke system.
Engine is running overloaded - Load reducing is recommended.
Too lean fuel mixture in carburetor - Set the carburetor correctly.
Incorrect ignition timing - Ignition timing needs to be adjusted correctly.
Thermostat failure - Install new thermostat.
Defective water pump - Change water pump as required.
Improper propeller diameter or pitch - Replace propeller.
Damaged or bent propeller - Replace propeller.
Outboard motor is positioned too low or too high - Position the engine correctly.
Low engine oil level - Add oil to the engine crankcase.
Oil pump malfunction - Replace oil pump.
Water intake is blocked - Wash or clean as required.
Improper valve setting - Valves needs to be adjusted properly.
| Abnormal engine noise or knocking |
Low octane gasoline - Change fuel.
Engine overload - Load reducing required.
Low idle speed setting is incorrect - Correct idle settings.
Fuel pump is defective or dirty - Service or replace fuel pump.
Crankshaft or main bearings wear - Change defective components as required.
Worn piston rings or cylinder bore - Change defective parts.
| Engine power is insufficient |
Carburetor is dirty or improperly adjusted - Clean or correctly adjust carburetor.
Dirty or damaged fuel pump - Clean or install new fuel pump.
Ignition system failure - Check ignition and replace faulty components.
Worn cylinder head gasket - Replace the head gasket.
Faulty powerhead components - Replace defective components.
Valves are stuck or burned - Clean or change valves.
Propeller pitch or diameter incorrect - Install correct propeller.
Damaged or bent propeller - Replace propeller.
Engine mounted at wrong transom height - Check the outboard motor mounting height.
Trim angle is incorrect - Adjust trim angle correctly.
| Engine uses too much fuel |
Incorrect adjustment of carburetor main jet - Adjust the carburetor main jet correctly.
Loose or faulty spark plug - Tighten or replace spark plug.
Rings, sleeve, or piston are damaged - Replace faulty parts as required.
| Excessive motor vibration |
Damaged or bent propeller - Replace propeller.
Propeller shaft damaged - Replace propeller shaft.
Weeds wraped around propeller - Clean the propeller.
Motor mounting bolt is loose - Tighten the bolt as required.
Loose or faulty steering pivot Tighten correctly or replace.
Battery voltage is low - Recharge the battery.
Battery runs out quickly - Service or change the battery.
Battery terminals are corroded or wires are disconnected - Connect wiring properly or install new terminals.
Starter motor failure - Repair or replace starter.
| Trim motor runs but trim system does not move up or down |
Insufficient oil - Checking oil level and add if necessary.
Damaged pump assembly - Check pump and replace if necessary.
Leakage of manual drain valve - Close the valve fully or replace it.
Faulty pump driveshaft or motor - Replace worn component.
| Trim cannot be fully up or down |
Defective pump assembly - Change pump.
Tilt ram piston ball is not positioned correctly - Service or repair.
Tilt ram piston O-ring damaged - Replace O-ring.
Not enough oil - Checking oil level and add if necessary.
Lower check valve not seating in port side trim ram - Secure valve properly.
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