Check and clean the vent. 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.
How do you fix a surging idle?
Turn the engine off again, and reattach the air intake duct work to the throttle body. Start the engine and rev and hold to 1,500 to 2,000 rpm until no white smoke is coming out of the exhaust pipe. Cleaning the Idle Air Speed Control Valve with aerosol throttle cleaner can often solve an idle problem.
What causes 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.
Can bad spark plugs cause surging?
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.
What can cause a fluctuating idle?
Erratic engine idle can be caused by various factors, but the most common and likely cause is a dirty or malfunctioning Mass Air Flow (MAF) sensor. … This causes erroneous readings by the engine control unit, leading to incorrect fuel injection quantities.
Why does my car rev up and down while idling?
The idle is controlled by the idle air control valve and if it cannot keep the engine idling it will keep trying to rev the engine up to compensate. A vacuum leak, sensor that has failed, or an EGR system malfunction could potentially be the cause of the erratic engine you’re experiencing.
Why does my Briggs and Stratton engine backfire?
Shutting off the engine at high RPM, causing fuel to pump through the engine for ignition. Gasoline that contains alcohol has a tendency to ignite easier, which can cause afterfire. … Carburetor adjustment may not be properly set for correct engine performance. Anti-afterfire solenoid may not be working properly.
What does car surging mean?
Surging is associated with a sudden increase in speed that occurs while trying to maintain a constant one. This is a sign that your fuel pump may have sufficient wear and tear and that its irregular resistance within the motor is creating an inability to maintain consistent pressure resulting in surges of power.
Why is my mower idling low?
A lawn mower’s engine continues to run at low speeds when idling, pulling just enough fuel and air into the carburetor to keep combustion going. If the mower doesn’t idle properly, it’s usually because of a loss of fuel or air in the carburetor at these low speeds.