0307087 EVINRUDE SCREW ASSY., Gearcase head

Checking Coolant Level
With the engine stopped:1. Slowly turn the filler cap to the first stop and release pressure.
Be careful. If the engine is warm-steam may spray outward under high pressure.
2. Push the cap down; turn until the cap is released.3. Maintain level to base of fill pipe. The coolant requires expansion space as it is heated.4. Make-up coolant should be one of the following, in the order of preference: a. Permanent antifreeze and water solution.b. Drinkable water and rust inhibitor solution.(a) Must be used if engine is to be shut down in below freezing weather without draining the coolant. (b) Can only be used when the coolant temperature is above freezing, or if the coolant will be immediately drained after shutdown during below freezing temperatures.Checking Water Temperature Gauge Reading
The water temperature gauge should normally register in the NORMAL range when operating.1. If the water temperature gauge continually registers near or in the HOT range without boiling, have the system checked to determine if the cooling system is functioning properly.2. Frequently check the water temperature gauge while operating. Be sure to note any deviation from the normal reading.3. Whenever the reading changes, investigate the cause and have necessary repairs made.Draining Complete Cooling System
1. Remove the water pump drain plug.2. Remove the engine block right rear drain cover.3. Remove the drain plug from the rear of the oil cooler support. 4. Remove the engine block left front drain cover. 5. Remove the left and right manifold water shield drain plug. 6. Remove the engine block left rear drain cover.7. Remove the elbow drain plug from the left side of the flywheel housing. 8. Remove the aftercooler drain plug.Allow the coolant to drain. 9. Install all drain covers and plugs. Close the radiator drain valve.Flushing Cooling System
To clean the cooling system, any good commercial radiator cleaning solution can be used. Follow the instructions included with the cleaner.The cooling system can be cleaned using oxalic acid and sodium carbonate as follows: 1. Fill the cooling system with a solution consisting of two pounds of oxalic acid or sodium bisulphate (NaHSO4) with every 10 gallons of water (mix 0.24 kg with every 10 litres of water).2. Start the engine and operate at operating temperatures for 1/2 to 1 hour.3. Stop the engine and drain the cooling system.4. Flush the system with clean water until the draining water is clear.5. Install all drain plugs.6. Fill with a solution consisting of 1/2 pound of sodium carbonate crystals (Na2CO3) with every 10 gallons of water (mix 0.06 kg with every 10 litres of water).7. Start and run the engine for 10 minutes.8. Stop the engine and drain the cooling system.9. Flush the cooling system with clean water.10. Install all drain plugs.Filling Cooling System
1. Add the correct amount of antifreeze and Caterpillar Corrosion Inhibitor. Be sure to follow instructions on the container. Do not add Caterpillar Corrosion Inhibitor to Dowtherm 209.2. Fill to the correct level with water which is free as possible from scale forming minerals.3. Start and run the engine for 10 minutes.4. Check the coolant level. Add coolant if necessary. Do not fill to the top of the filler tube, leave space for expansion.5. Install the filler cap.