1. Fuel shutoff valve: Check to make sure that the fuel shutoff valve is functioning properly and is completely closed when the tractor is not in use. When the fuel shutoff valve is worn or damaged, it may not be able to completely shut off the fuel supply, allowing gas to continue flowing into the engine and eventually mixing with the oil.
2. Carburetor float valve: The carburetor float valve is responsible for regulating the fuel level in the carburetor. If the float valve is worn, damaged, or not properly adjusted, it can cause the fuel level in the carburetor to become too high, allowing fuel to overflow and enter the engine oil.
3. Carburetor needle valve: The carburetor needle valve controls the flow of fuel from the carburetor into the engine. If the needle valve is worn, damaged, or not properly adjusted, it can cause the engine to run rich, resulting in unburned fuel entering the oil.
4. Cylinder head gasket: The cylinder head gasket seals the combustion chamber between the cylinder head and the engine block. If the cylinder head gasket is worn, damaged, or not properly installed, it can allow combustion gases and unburned fuel to leak into the oil.
5. Piston rings: The piston rings seal the combustion chamber between the piston and the cylinder walls. If the piston rings are worn, damaged, or not properly installed, they can allow combustion gases and unburned fuel to leak into the oil.
It's important to note that diagnosing and repairing this issue may require specific knowledge and expertise. If you're not comfortable working on small engines or lack the necessary tools, it's recommended to consult with a professional mechanic or a Bolens authorized service center for assistance and repairs.
