846673 Mercruiser WASHER

COMPRESSION PRESSURE MEASUREMENT
1. Inspection Check to make sure -(1) The crankcase oil level is correct, and the air cleaner, starter and battery are all in normal condition.(2) The engine is at the normal operating temperature.2. Measurement (1) Move the control lever to a position for shutting off fuel supply.(2) Remove all glow plugs from the engine. Install the compression gauge and adapter (ST332270) combination to a cylinder on which the compression pressure is to be measured.
Compression gauge and adaptor
Measuring compression pressure(3) Turn the engine with the starter and read the gauge pressure at the instant the gauge pointer comes to stop.(4) If the gauge reading is below the limit, overhaul the engine.
a) Be sure to measure the compression pressure on all cylinders.b) The compression pressure varies with change of engine rpm. This makes it necessary to check engine rpm at the time of measuring the compression pressure.
a) It is important to measure the compression pressure at regular intervals to obtain the data on the gradual change of the compression pressure.b) The compression pressure would be slightly higher than the standard in a new or overhauled engine owing to break-in of the piston rings, valve seats, etc. It drops as the engine components wear down.
TROUBLESHOOTING
1. GeneralThe diagnosis of troubles, especially those caused by a faulty fuel injection pump or injection nozzles, or low compression pressure, can be difficult. It requires a careful inspection to determine not which item is the cause, but how many causes are contributing to the cause. Several causes may be contributing to a single trouble.On the following pages, there are troubleshooting charts on which engine troubles can be traced to their causes. Each chart has items to be verified ahead and suggested inspection procedure.Diesel engines exhibit some marked characteristics during operation. Knowing these characteristics will help minimize time lost in tracing engine troubles to their source. Following are the characteristics of diesel engines you should know about for diagnosis:* Combustion know (diesel knock)* Some black exhaust smoke (when the engine picks up load)* Vibration (due to high compression pressure and high torque)* Hunting (when the engine speed is quickly decreased)* Some white exhaust smoke (when the engine is cold, or shortly after the engine has been started) 2. Engine troubleshooting Problem 1: Hard starting(1) Items to be checked for ahead* Clogged air cleaner* Wrong oil grade for weather conditions * Poor quality fuel* Low cranking speed(2) Inspection procedure Problem 2: Fuel knockMore or less fuel knock occurs in diesel engines. This may be caused either by an excessively large delay period or by a too fast rate of fuel injection.(1) Items to be checked for ahead* Clogged air cleaner* Poor quality fuel(2) Inspection procedure Problem 3: Overheating(1) Items to be checked for aheadOverheating might also be caused by abnormal operating conditions. If the engine is overheating but its cooling system is not contributing to this trouble, it is necessary to check the difference between the ambient temperature and coolant temperature when the engine is in normal operation (with the thermostat fully open). If the ambient temperature is higher than the normal coolant temperature by more than 60°C (108°C), investigate other items than those related to the engine cooling system.* Insufficient coolant and exterior coolant leaks* Loose fan belt* Radiator core openings plugged with dirt(2) Inspection procedure Problem 4: Black exhaust smoke(1) Items to be checked for ahead* Clogged air cleaner* Poor quality fuel(2) Inspection procedure Problem 5: Erratic idle speeds(1) Items to be checked for ahead* Maladjusted engine control* Wrong oil grade for weather conditions * Poor quality fuel(2) Inspection procedure Problem 6: Low power or loss of power(1) Items to be checked for ahead* Stuck running parts* Wrong oil grade for weather conditions * Poor quality fuel* Clogged air cleaner* Restricted exhaust line* Faulty power take-off(2) Inspection procedure 3. Starting system troubleshooting BASIC PRECAUTIONS FOR DISASSEMBLY AND ASSEMBLY
This section outlines basic precautions recommended by Mitsubishi that should always be observed.1. Disassembly (1) Always use tools that are in good condition and be sure you understand how to use them before performing any job. (2) Use an overhaul stand or a work bench, it necessary. Also, use bins to keep engine parts in order of removal.(3) Parts must be restored to their respective components from which they were removed at disassembly. This means that all parts must be set aside separately in groups, each marked for its component, so that the same combination or set can be reproduced at assembly.(4) Pay attention to marks on assemblies, components and parts for their positions or directions. Put on marks, if necessary, to aid assembly.(5) Carefully check each part or component for any sign of faulty condition during removal or cleaning. The part will tell you how it acted or what was abnormal about it more accurately during removal or cleaning. (6) When lifting or carrying a part too heavy or too awkward for one person to handle, get another person's help and, if necessary, use a jack or a hoist.2. Assembly (1) Wash all parts, except for oil s