815431 Mercury SCREW, (M14 x 178)

Illustration 1 g01106438
Boiling point of water
Remember that temperature and pressure work together. When a diagnosis is made of a cooling system problem, temperature and pressure must be checked. Cooling system pressure will have an effect on the cooling system temperature. For an example, refer to Illustration 1. This will show the effect of pressure on the boiling point (steam) of water. This will also show the effect of height above sea level.
Personal injury can result from hot coolant, steam and alkali.At operating temperature, engine coolant is hot and under pressure. The radiator and all lines to heaters or the engine contain hot coolant or steam. Any contact can cause severe burns.Remove filler cap slowly to relieve pressure only when engine is stopped and radiator cap is cool enough to touch with your bare hand.Cooling System Conditioner contains alkali. Avoid contact with skin and eyes.
The coolant level must be to the correct level in order to check the coolant system. The engine must be cold and the engine must not be running. After the engine is cool, loosen the pressure cap in order to relieve the pressure out of the cooling system. Then remove the pressure cap.The level of the coolant should not be more than 13 mm (0.5 inch) from the bottom of the filler pipe. If the cooling system is equipped with a sight glass, the coolant should be to the proper level in the sight glass.Test Tools For Cooling System
Table 1
Tools Needed
Part Number Part Name Quantity
4C-6500 Digital Thermometer 1
9S-8140 Pressurizing Pump 1
9U-7400 Multitach Tool Group 1
245-5829 Coolant/Battery Tester Gp 1
Making contact with a running engine can cause burns from hot parts and can cause injury from rotating parts.When working on an engine that is running, avoid contact with hot parts and rotating parts.
Illustration 2 g00313246
4C-6500 Digital Thermometer
The 4C-6500 Digital Thermometer is used in the diagnosis of overheating conditions and in the diagnosis of overcooling conditions. This group can be used to check temperatures in several different parts of the cooling system. Refer to Operating Manual, NEHS0554, " 4C-6500 Digital Thermometer Group" for the testing procedure.
Illustration 3 g00286276
9U-7400 Multitach
The 9U-7400 Multitach Tool Group is used to check the fan speed. Refer to Operating Manual, NEHS0605, "Tool Operating Manual (9U-7400 Multitach II Group, 9U-7401 Multitach II, 9U-7402 Multitach Photo Group)" for the testing procedure.
Illustration 4 g00286369
9S-8140 Pressurizing Pump
The 9S-8140 Pressurizing Pump is used to test the filler caps. This pressurizing pump is also used to pressure test the cooling system for leaks.Check the coolant frequently in cold weather for the proper glycol concentration. Use the 245-5829 Coolant/Battery Tester Gp in order to ensure adequate freeze protection. The tester gives immediate, accurate readings. The tester can be used for coolants that contain ethylene or propylene glycol. Refer to the Operation and Maintenance Manual for additional information on the correct coolant mixture.Checking the Coolant Recovery System
The following information will aid in troubleshooting problems that could be found during a routine check of the cooling system on a marine engine.
Table 2
Tools Needed
Part Number Part Name Quantity
9S-8140 Pressurizing Pump 1 The Recovery Bottle is Overflowing
The following items should be checked when a recovery bottle overflows.
Verify that no air is trapped in the cooling system. Refer to Testing and Adjusting, "Cooling System - Check".
Verify that the recovery bottle is not overfilled when the engine is cold.
Verify that the operating temperatures of the engine are correct. Leaking Coolant is Visible on Top of the Expansion Tank
The following items should be checked if coolant leaks from the top of the expansion tank.
Verify that the recovery bottle is ventilated to the atmosphere and verify that there is not an obstruction in the vent.
Remove the pressure cap on the expansion tank and check for foreign material between the top seal of the cap and the top of the filler neck. If foreign material is present, clean the cap and reinstall the cap.
Check the condition of the filler neck on the expansion tank. If the filler neck is distorted, replace the filler neck. Also, if the neck c