10170D50 Mariner OWNERS MANUAL, 40/50 2-Stroke

Troubleshooting
Troubleshooting can be difficult. The Troubleshooting Index gives a list of possible problems. To make a repair to a problem, make reference to the cause and correction on the pages that follow.This list of problems, causes and corrections will only give an indication of where a possible problem can be, and what repairs are needed. Normally, more or other repair work is needed beyond the recommendation in the list.Remember that a problem is not normally caused only by one part, but by the relation of one part with other parts. This list is only a guide and cannot give all possible problems and corrections. Service personnel must find the problem and its source, then make the necessary repairs.Troubleshooting Index
1. Engine Will Not Turn When Start Switch Is On.2. Engine Will Not Start.3. Misfiring Or Running Rough.4. Stall At Low rpm.5. Sudden Changes In Engine rpm.6. Not Enough Power.7. Too Much Vibration.8. Loud Combustion Noise.9. Loud Noise (Clicking) From Valve Compartment.10. Oil In Cooling System.11. Mechanical Noise (Knock) In Engine.12. Fuel Consumption Too High.13. Loud Noise From Valves Or Valve Operating Components.14. Little Movement Of Rocker Arm And Too Much Valve Clearance.15. Valve Rotocoil Or Spring Lock Is Free.16. Oil At The Exhaust.17. Little Or No Valve Clearance.18. Engine Has Early Wear.19. Coolant In Lubrication Oil.20. Too Much Black Or Gray Smoke.21. Too Much White Or Blue Smoke.22. Engine Has Low Oil Pressure.23. Engine Uses Too Much Lubrication Oil.24. Engine Coolant Is Too Hot.25. Exhaust Temperature Is Too High.26. Starter Motor Does Not Turn.27. Alternator Gives No Charge.28. Alternator Charge Rate Is Low Or Not Regular.29. Alternator Charge Is Too High.30. Alternator Has Noise.Problem 1: Engine Crankshaft Will Not Turn When Start Switch Is On
Probable Cause:1. Battery Has Low Output: Make Reference to Problem 27.2. Wires Or Switches Have Defect: Make Reference to Problem 27.3. Starter Motor Solenoid Has A Defect: Make Reference to Problem 26.4. Starter Motor Has A Defect: Make Reference to Problem 26.5. Inside Problem Prevents Engine Crankshaft From Turning: If the crankshaft cannot be turned after the drive equipment is disconnected, remove the fuel nozzles and check for fluid in the cylinders while the crankshaft is turned. If fluid in the cylinders is not the problem, the engine must be disassembled to check for other inside problems. Some of these inside problems are bearing seizure, piston seizure, wrong pistons installed in the engine, and valves making contact with pistons.Problem 2: Engine Will Not Start
Probable Cause:1. Slow Cranking Speed: Make reference to Problem 27.2. No Fuel In The Housing For The Fuel Injection Pumps: Fill the housing for the fuel injection pumps with fuel with the priming pump. Remove the air with the bleed valve.3. Dirty Fuel Filter: Install new fuel filter.4. Dirty Or Broken Fuel Lines: Clean or install new fuel lines as necessary.5. No Fuel To Cylinders: Put fuel in fuel tank. "Prime" (remove the air and/or low quality fuel from the fuel system).6. Bad Quality Fuel: Remove the fuel from the fuel tank. Install a new fuel filter element. Put a good grade of clean fuel in the fuel tank.7. Fuel Has "Cloud Point" Higher Than Atmospheric Temperature ("Cloud Point" = Temperature Which Makes Wax Form In Fuel): Drain the fuel tank lines, and fuel injection pump housing. Change the fuel filter. Fill the tank with fuel which has the correct "cloud point" and remove the air from the system with the priming pump.8. Wrong Fuel Injection Timing: Make adjustment to timing.9. Over Fueling Spring Not Installed: Install over fueling spring.10. Fuel Ratio Control Has A Defect: Check fuel ratio control setting. Adjust if necessary.Problem 3: Misfiring Or Running Rough
Probable Cause:1. Air In The Fuel System: Find air leak in the fuel system and correct. Remove air from fuel system. See Fuel System in Testing and Adjusting.2. Fuel Pressure Is Low: Make sure there is fuel in the fuel tank. Look for leaks or bad bends in the fuel line between fuel tank and fuel transfer pump. Look for air in the fuel system. Check fuel pressure at the fuel injection pump housing. If fuel pressure at high idle is lower than 105 kPa (15 psi), install a new filter element. If fuel pressure is still low, check the pumping spring and the check valves in the fuel transfer pump.3. Leak Or Break In Fuel Line Between Injection Pump And Injection Valve: Install a new fuel line.4. Defect In Fuel Injection Valve(s) Or Injection Pump(s): Run engine at rpm that gives maximum misfiring or rough running. Then loosen a fuel line nut on the injection valve for each cylinder, one at a time. Find the cylinder where loosening the fuel line nut does not change the way the engine runs. Test the injection pump and injection valve for that cylinder. Install new parts where needed.5. Fuel System Not Timed Correctly To Engine: Make adjustment to timing if necessary.6. Wrong Valve Clearance: Make adjustment, See the Subject Valve Clearance in Testing and Adjusting.7. Bent Or Broken Push Rod: Replacement of push rod is necessary.8. Worn Valve Seat Or Face Of Valve: Reconditioning of cylinder head is needed.Problem 4: Stall At Low RPM
Probable Cause:1. Idle RPM Too Low: Make adjustments to governor so idle rpm is the same as given in the Fuel Setting And Related Information Fiche.2. Defect In Fuel Injection Valve(s) Or Fuel Injection Pump(s): Run engine at rpm that gives maximum misfiring or rough running. Then loosen a fuel line nut on the injection pump for each cylinder, one at a time. Find the cylinder where loosening the fuel line nut does not change the way the engine runs. Test the injection pump and injection valve for that cylinder. Install new parts where needed.Problem 5: Sudden Changes In Engine Speed (rpm)
Probable Cause:1. Failure Of Governor Or Fuel Injection Pump: Look for damaged or broken springs, linkage or other parts. Remove the governor. Check for free travel of the fuel rack. Be sure fuel injection pumps are installed correctly. Check for correct governor