Engine: Blows White Smoke From Exhaust

The head gasket creates the seal between the engine block and cylinder head for compression, and provides a tight seal for oil and coolant passages. White smoke from the exhaust is a result of antifreeze entering the combustion chamber. This is a clear indicator of a blown head gasket. Remove the spark plug (or plugs). If you have a bright, shiny plug, it indicates the cylinder has antifreeze entering it. When the antifreeze burns with the air/fuel mixture, the water in the antifreeze turns into a vapor, basically steam-cleaning the inside of the combustion chamber. That is why the spark plug is bright and shiny. The head gasket, at this point, has to be replaced. First, drain all fluids. Remove the air filter housing along with the air filter itself, then remove the carburetor, disconnecting the fuel line and removing the linkage. Remove the muffler from the cylinder head, and remove the valve cover bolts and cover with the gasket. Pull the valve cover off. Remove all the bolts holding the cylinder head to the engine block in a diagonal pattern, to prevent warping of the cylinder head. Remove the head and pull off the old head gasket. Clean both surfaces of the engine block and cylinder head with a soft cloth, being careful not to damage this area, as you want a tight seal for the gasket. Install the new gasket and reassemble. It is best to replace all the cylinder head bolts with new ones, as these are usually a one-time use because of the pressure and abuse they take. Tighten down the cylinder head bolts in an alternating pattern to prevent warping the cylinder head. Check manufacturer specs for tightness. These bolts must be torqued for a proper seal. Reinstall the carburetor, hooking the fuel line and linkage back up, then reinstall the air filter housing with air filter, muffler, and valve cover with the new valve cover gasket.