8866A81 Mercruiser GEAR HOUSING ASSEMBLY, (15/17), Complete

Illustration 1 g00921815
Boiling point of water
Temperature and pressure work together. When a diagnosis is made of a cooling system problem, temperature and pressure must be checked. Cooling system pressure affects the cooling system temperature. For an example, refer to Illustration 1.The illustration shows the effect of pressure on the boiling point (steam) of water and also shows 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
348-5430 Multi-Tool Gp 1
259-6237 Coolant Tester Gp 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 g02167834
348-5430 Multi-Tool Gp
The 348-5430 Multi-Tool Gp 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 Tool Operating Manual, NEHS1087, " 348-5430 Multi-Tool Gp" for the testing procedure.The 348-5430 Multi-Tool Gp is used to check the air flow through the radiator core. Refer to Tool Operating Manual, NEHS1087 for the test procedure for checking the air flow through the radiator core.The 348-5430 Multi-Tool Gp is used to check the fan speed. Refer to Tool Operating Manual, NEHS1087 for the testing procedure.The 348-5430 Multi-Tool Gp can measure engine rpm from a magnetic pickup. The magnetic pickup is located in the flywheel housing. Refer to Tool Operating Manual, NEHS1087 for the testing procedure.The 348-5430 Multi-Tool Gp is also a photo-tachometer that is held by hand for general use. The multi-tool can measure the engine speed by placing a piece of reflective tape on the crankshaft pulley.
Illustration 3 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.
Illustration 4 g00439083
245-5829 Coolant/Battery Tester Gp
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 antifreeze and coolants that contain ethylene or propylene glycol. Making the Correct Antifreeze Mixtures
Refer to the Operation and Maintenance Manual for the correct coolant recommendations for your individual application.Checking the Filler Cap
Table 2
Tools Needed
Part Number Part Name Quantity
9S-8140 Pressurizing Pump 1 One cause for a pressure loss in the cooling system can be a damaged seal on the radiator filler cap.
Illustration 5 g01096114
Typical schematic of filler cap
(1) Sealing surface of both filler cap and radiator