Smoke from the Exhaust
* Oil Consumption: The most likely cause of smoke from the exhaust is oil consumption. This could be due to worn piston rings, valve seals, or a blown head gasket. In these cases, oil is getting past the piston rings into the combustion chamber and burning with the fuel, creating blue or white smoke.
* Fuel/Air Mixture: An overly rich fuel mixture can also cause smoke. This could be due to a clogged air filter, a faulty carburetor, or even incorrect fuel levels.
* Water Contamination: Water in the fuel or the combustion chamber can create a white or gray smoke. This is usually a sign of a problem with your fuel tank or fuel lines.
Oil Getting into the Intake
* Valve Stem Seals: Worn valve stem seals can allow oil to seep past the valves and into the intake manifold. This will cause blue smoke, especially during acceleration or when the engine is cold.
* Oil Overfill: Simply overfilling your engine with oil can cause it to leak into the intake manifold, as there's nowhere else for the excess oil to go.
* Crankcase Ventilation System: A clogged or malfunctioning crankcase ventilation system (PCV valve) can cause oil to be drawn into the intake manifold.
What You Should Do
1. Check the Oil Level: Make sure you haven't overfilled the engine. If the oil level is too high, drain some out.
2. Inspect the Air Filter: A clogged air filter can lead to a rich fuel mixture. Replace the filter if necessary.
3. Check for Fuel Leaks: Inspect the fuel lines and tank for any leaks.
4. Examine the Spark Plug: A fouled spark plug can be a symptom of a rich fuel mixture. Clean or replace the spark plug as needed.
5. Check for Signs of Oil Consumption: If you see blue or white smoke, you likely have an oil consumption problem. You'll need to get the engine inspected by a mechanic.
6. Inspect the Engine for Leaks: Check the valve covers, oil pan, and other areas for oil leaks.
7. Consult a Mechanic: If you can't identify the problem or if you suspect serious engine damage, it's best to take your lawnmower to a qualified mechanic for diagnosis and repair.
Important Note: If your engine is experiencing oil consumption, it's crucial to address the issue quickly to prevent further damage. Ignoring the problem can lead to engine seizing and costly repairs.
