NOTE: Not all Atomic 4 engines are the same. This is how mine looks and how I winterize it – yours might be different. Click on the pictures to see the labeling.
1. Drain the engine by removing 2 drain plugs from the engine block, 1 plug from the exhaust manifold and 1 from the muffler. One engine block drain plug is located at the front of the engine beside where the starter attaches to the block. The other engine block drain plug is located behind the starter below the alternator. The drain plug on the exhaust manifold is located at the rear back of the manifold on the right hand side of the engine. The muffler drain plug is at the bottom of the muffler stack. Make sure the water flows freely from all of drain plugs. If not, fish around inside the holes with a wire to clear out any crud.
2. Replace all the drain plugs once all the water has drained out of the engine.
3. Close off your raw water intake and switch over to your ‘T’ intake which you will put in your bucket of antifreeze. If you do not have a ‘T’ fitting installed, I have read of some people who pour the antifreeze into the raw water strainer instead.
6. Run engine until you have antifreeze coming out the exhaust. Then shut the engine off again.
7. Unpinch the bypass hose. Open up the thermostat housing again and reinstall the thermostat.
9. Remove all the spark plugs and spray fogging oil into the cylinders. You might want to clean off the area around the spark plugs before removing them to prevent chips of rust and paint from falling into the spark plug holes.
10. Turn off the gas supply to the engine and then turn the engine over briefly with the plugs still removed to move the fogging spray into the cylinders. If you have the hand crank for the Atomic 4, you can also just crank the engine over by hand.
11. Reinstall the plugs.
12. Open up your raw water strainer and pour in some antifreeze.
13. Leave your raw water thru hull closed until spring.
14. Top up your gas tank and add gasoline stabilizer.
15. Bobs your uncle, Betty’s your aunt – your done!