855381 Mercruiser MOUNT

Troubleshooting Problem List
The Engine Crankshaft Will Not Turn When The Start Switch Is On.
The Engine Will Not Start.
The Engine Is Misfiring Or The Engine Is Running Rough.
The Engine Stalls At Low RPM.
There Are Sudden Changes In Engine RPM.
The Engine Does Not Have Enough Power.
The Engine Has Too Much Vibration.
The Engine Has A Loud Combustion Noise (Sound).
The Engine Has a Valve Train Noise (Clicking).
Oil Is In The Cooling System.
Mechanical Noise (Knock) Is In The Engine.
Fuel Consumption Is Too High.
The Engine Has A Loud Noise From The Valves Or The Valve Drive Components.
Little Movement Of The Rocker Arm And Too Much Valve Lash Is Present.
The Valve Keeper Or The Spring Is Broken.
Oil Is At The Exhaust.
Little Valve Lash Or No Valve Lash Is Present.
The Engine Has Early Wear.
Coolant Is In The Lubrication Oil.
Too Much Black Smoke Or Gray Smoke Is Present.
Too Much White Smoke Or Blue Smoke Is Present.
The Engine Has Low Oil Pressure.
The Engine Uses Too Much Lubrication Oil.
The Engine Coolant Is Too Hot.
The Starting Motor Does Not Turn.
The Alternator Gives No Charge.
The Alternator Charge Rate Is Low Or Irregular.
The Alternator Charge Is Too High.
The Alternator Has Noise.
The Exhaust Temperature Is Too High.Troubleshooting Problems
Problem 1
The Engine Crankshaft Will Not Turn When The Start Switch Is On.Probable Cause
Low Output From The BatteryCheck the condition of the battery. Charge the battery or replace the battery, if necessary.
Damaged Wires or SwitchesRepair any parts or replace any parts, if necessary.
Damaged Starting Motor SolenoidInstall a new solenoid.
Damaged Starting MotorRepair the starting motor or replace the starting motor.
An Internal Problem Prevents The Turning Of The Engine Crankshaft.Disconnect the driven equipment. Remove the fuel injection nozzles if the crankshaft cannot be turned. Inspect the cylinders for fluid while the crankshaft is being turned. If fluid in the cylinders is not the problem, the engine must be disassembled. After you disassemble the engine, inspect the engine for other internal problems. Possible internal problems include the following conditions:
Bearing seizure
Piston seizure
Incorrect pistons are installed in the engine.Problem 2
The Engine Will Not Start.Probable Cause
The fuel tank is empty.Put fuel in the fuel tank.
Low Quality FuelRemove fuel from the fuel tank. Install a new fuel filter element. Put a good grade of clean fuel in the fuel tank.
Dirty Fuel FilterInstall a new fuel filter.
Broken Fuel Lines Or Dirty Fuel LinesFuel lines should be cleaned or new fuel lines should be installed, if necessary.
The Fuel Pressure is Too Low.Replace the fuel filter. Inspect the bypass valve for free movement. Install a new bypass valve, if necessary.
Air is in the Fuel System.Find the air leak in the fuel system and correct the leak. Remove air from the fuel system.
Wrong Fuel Injection TimingAdjust the fuel injection timing, if necessary.
The Constant Purge Valve Stays Open. (There Is Insufficient Fuel Pressure for Starting The Engine.)Replace the constant purge valve.
Slow Cranking SpeedCheck condition of battery. Replace the battery, if necessary.
No Fuel In The Housing For The Fuel Injection PumpsUse the priming pump in order to fill the housing for the fuel injection pumps with fuel.
The Fuel Has A Cloud Point That Is Higher Than The Atmospheric Temperature. (The Cloud Point Is The Temperature That Causes Wax To Form In Fuel.)Drain the fuel tank, the lines and the fuel injection pump housing. Change the fuel filter. Fill the tank with fuel that has the correct cloud point.Problem 3
The Engine Is Misfiring Or The Engine Is Running Rough.Probable Cause
Low Fuel PressureEnsure that there is enough fuel in the fuel tank. Inspect the fuel system for leaks. Inspect the fuel line between the fuel tank and the fuel transfer pump for bad bends. Inspect the fuel system for air. Check fuel pressure. The outlet pressure of the fuel transfer pump at full load speed is 75 to 100 kPa (10.9 to 24.7 psi). If the fuel pressure is lower, install a new fuel filter element. Inspect the fuel bypass valve for free movement. Install a new fuel bypass valve, if necessary.
Air In Fuel SystemFind the air leak in the fuel system and correct the air leak. Remove the air from the fuel system.
Leakage Or Breakage In Fuel Line Between Fuel Injection Pump And Fuel Injection ValveInstall a new fuel line.
Wrong Valve LashAdjust the valve lash. Refer to Testing And Adjusting.
Worn Fuel Injection NozzleRun the engine at an rpm that gives the maximum misfiring or rough running. Then, loosen a fuel line nut on the fuel injection nozzle for each cylinder one at a time. When a fuel line nut is loosened, the misfiring or rough running will increase. If loosening a fuel line nut does not affect the misfiring or rough running, test the fuel injection nozzle for that cylinder. Install new parts, if necessary.
Wrong Fuel Injection TimingAdjust the fuel injection timing.
Bent Pushrod Or Broken PushrodReplace the pushrod.
Worn Valve Seat Or Face Of ValveA reconditioning of the cylinder head is necessary.Problem 4
The Engine Stalls At Low RPM.Probable Cause
Fuel Pressure is Low.Ensure that enough fuel is in the fuel tank. Inspect the fuel system for leaks. Inspect the fuel line between the fuel tank and the fuel transfer pump for bad bends. Inspect the fuel system for air. Check fuel pressure. The outlet pressure of the fuel transfer pump at full load speed is 75 to 100 kPa (10.9 to 24.7 psi). If the fuel pressure is lower, install a new fuel filter element. Inspect the fuel bypass valve for free movement. Install a new fuel bypass valve, if necessary.
Low Engine Idle RPMMake adjustment to the governor. Ensure that the idle rpm setting matches the rpm that is listed in the Technical Marketing Information (TMI).
Worn Fuel Injection NozzleInstall a new fuel injection nozzle.
Wrong Valve LashAdjust the valve lash. Refer to the Technical Marketing Information (TMI) or refer to the Fuel Setting and Related Information Microfiche for the correct idle rpm.Problem 5
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