0438545 EVINRUDE IMPELLER HOUSING

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.
Introduction
This engine has a pressurized cooling system. A pressurized cooling system has two advantages. The cooling system can be operated in a safe manner at a temperature higher than the normal boiling point (steam) of water.This type of system prevents cavitation in the water pump. Cavitation is the forming of low-pressure bubbles in liquids that are caused by mechanical forces. The formation of an air pocket or a steam pocket in this type of cooling system is difficult.
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.The coolant level must be to the correct level 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 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.References
Reference: Tool Operating Manual, NEHS1087, " 348-5430 Multi-Tool Gp"Reference: Operation and Maintenance Manual , Fluid RecommendationsReference: Troubleshooting, "Coolant Level is Low"Required Tools
Table 1
Required Tools
Item Quantity Part Number Part Name
T1 1 348-5430 Multi-Tool Gp
T2 1 259-6237 Coolant Tester Gp
T3 1 245-5829 Coolant/Battery Tester Gp
T4 1 9S-8140 Pressurizing Pump
Illustration 2 g06501035
348-5430 Multi-Tool Gp
The Multi-Tool Group (T1) can be used for the following testing:
Diagnosis of overheating conditions and in the diagnosis of over-cooling conditions
Check temperatures in several different parts of the cooling system
Check the air flow through the radiator core
Checking the fan speed
Measure engine rpm from a magnetic pickup located in the flywheel housing
Used as 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 pulleyReference: All tests using the multi-tool group are covered in Tool Operating Manual, NEHS1087, " 348-5430 Multi-Tool Gp".
Illustration 3 g06501062
(T4) 9S-8140 Pressurizing PumpPressurizing pump (T4) is used to test the filler caps. This pressurizing pump is also used to pressure test the cooling system for leaks.
Illustration 4 g06501068
(T3) 245-5829 Coolant/Battery Tester GpCheck the coolant frequently in cold weather for the proper glycol concentration. Use the Coolant/Battery Tester Group (T3) 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.Procedure to Make the Correct Antifreeze Mixture
Refer to the Operation and Maintenance Manual , Fluid Recommendations for the correct coolant recommendations for your individual application.Checking the Filler Cap Procedure
Table 2
Required Tools
Item Quantity Part Number Part Name
T4 1 9S-8140 Pressurizing Pump One cause for a pressure loss in the cooling system can be a damaged seal on the radiator filler cap.