What causes a lawn mower engine to surge?
Problems in the Fuel System
The cap on your mower’s gas tank is vented with a small hole. … Surging is also caused by water that got into the fuel. A mower left in a heavy rain or condensation on a hot summer day can choke the engine. Empty the gas tank, properly dispose of the old fuel and try a fresh batch of gasoline.
What is the cause of engine surging?
If an engine is not getting enough fuel (this is called “running lean”), due to fuel pressure (regulated by the fuel pump and regulator), restricted fuel injectors, a vacuum leak or really anything that throws off the fuel mixture going in to the engine, this can cause the surge.
What causes mower to rev up and down?
Airflow Issues. A lawnmower that hunts and surges may be experiencing something as simple as an airflow issue. If the air that the engine requires to run is blocked, especially sporadically, it can cause the engine to slow down. When the blockage moves or clears, the engine may suddenly rev up in response.
What causes a carbureted engine to surge?
Incorrect fuel mixture adjustments and engine idling capabilities can be upset by fuel mixture adjustments and fuel vapor recovery system malfunction. The fuel system cleaner added to the fuel tank can open blocked passages in the fuel system that could be causing the surge.
Why is my Husqvarna lawn mower surging?
The most common reason for a surging lawn mower engine is a blockage in the fuel supply, but there are other possibilities: Bad gas. Bad spark plug. Dirty / faulty carburetor.
Can spark plugs cause surging?
3. Surging and Lagging. Another good indication that your spark plugs are dirty or worn is if your vehicle experiences surges of speed, resulting in a jerking acceleration. These surges occur because your spark plugs are not igniting the fuel in your engine at the proper rate, resulting in an uneven speed.
How do I fix my lawn mower from sputtering?
How to Fix a Sputtering Lawnmower
- Remove the cap of the gas tank and look in at the gas. Inspect the gas for signs of water. …
- Turn the mower over so the oil case is sitting under the carburetor. …
- Remove the screw holding the air filter cover in place. …
- Check the underside of the unit for caked on grass.
Can faulty oxygen sensor cause engine surging?
Oxygen sensors are among the most interesting and important sensors on your engine. … Surging is among the many problems a failing O2 sensor can cause, but it isn’t the only one.
Why is my truck revving by itself?
It sounds like you may have a dirty or failing idle air control valve. … This valve is controlled by the vehicle’s computer and will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage.
Can a bad fuel filter cause surging?
Clogged Fuel Filter
Clogged filters cause surging because they reduce fuel pressure. In other words, the fuel injectors need to open to keep the amount flowing steadily. … This brings the pressure down again. To avoid this sort of pressure drop and spikes, you should check your fuel filter from time to time.
Why is my lawn mower not running smoothly?
If your lawn mower cuts out, smokes, idles poorly, vibrates or runs erratically, it could need a good tune-up to replace the spark plug, oil and air filter. Or the problem could be with the lawn mower’s fuel system. Rebuild or replace the carburetor if the engine isn’t getting a good supply of fuel.
Why is my lawn mower not getting gas?
The engine can’t get gas if the fuel filter is plugged or the carburetor inlet needle is stuck. Check the fuel filter (if equipped) by removing the fuel line at the carburetor. … If you still don’t get any gas, the fuel line is kinked or plugged. And check inside the tank for any debris that might clog the outlet.