Diagnosis and elimination of excessive fuel consumption of outboard motors

The engine is an important power component of the outboard motor. However, the engine consumes too much fuel during use. Once this problem occurs, the outboard motor manufacturer suggests that the following methods can be used to diagnose and eliminate it.
1. Check engine mechanical faults (cylinder pressure, valve stagnation or leakage, camshaft surface wear, valve timing, valve clearance, valve sealing, etc.), check whether the exhaust system is blocked, and the working condition of the cooling system thermostat .
2. Check whether the cold start fuel injection control is normal. Use a voltmeter or a test lamp to connect to the harness connector of the cold start fuel injector, and check whether the working duration of the cold start fuel injector meets the standard value when the engine is started. If the working time is too long or it keeps working after starting, it means that the control of the cold start injector is abnormal, and the cold start temperature switch and control circuit should be checked.
3. Check the ignition high pressure, energy, and ignition timing, and pay attention to dismantling the injectors to check whether there is any oil leakage in each injector. If abnormal, clean or replace the injector.
4. Check the throttle position sensor. When the throttle valve is at a small or medium opening, the full load switch should be disconnected. If the full-load switch is always closed or the closing time is too early, the computer will always or prematurely perform full-load enrichment, thereby increasing fuel consumption.
5. Check the air flow meter or intake pressure sensor, and its value should meet the standard. The error of the air flow meter or intake pressure sensor will directly affect the fuel injection quantity. If the test result is abnormal, replace the air flow meter or intake pressure sensor.
6. Measure the fuel pressure. The fuel pressure at idle speed should be about 250kPa. As the throttle is opened, the fuel pressure should gradually rise. The fuel pressure when the throttle valve is fully open is about 300kPa. If the fuel pressure can change with the throttle opening, but the pressure is always high, it means that the oil pressure regulator is faulty and should be replaced.
7. Measure the coolant temperature sensor, and its resistance value at different temperatures should meet the standard. If the resistance is too large, the computer will mistakenly think that the engine is in a low temperature state, and thus perform cold car enrichment control, which will increase fuel consumption. It can also be detected with a computer decoder, and the coolant temperature sensor displayed on the detector is sent to the computer to compare the coolant temperature value with the actual engine coolant temperature. If there is a difference, the coolant temperature sensor is faulty and should be replaced.