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.
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.
Why is my Briggs and Stratton 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.
What are the signs of a vacuum leak?
Here are four signs that your vehicle has a vacuum leak.
- Sporadic Idling. A vacuum leak introduces excess air into the engine, and this directly affects how your engine runs. …
- Engine Hesitation. Your engine trouble will not be limited to your idling if you have a leak. …
- Vacuum Sounds. …
- 4 Check Engine Warning.
Can a bad O2 sensor cause 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.
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.
Is it normal for RPM to fluctuate at idle?
Oftentimes, when your RPM fluctuates while accelerating, it’s going to be because of an issue with the idle air control valve, or IAC, in your car. The IAC is in charge of controlling the idle speed of your engine, and it could be the reason why your tachometer is out of control right now.
What does engine surging feel like?
You can even experience a bit of a delay when trying to accelerate. Moreover, it’s common for you to hear some noises coming from your engine during car surges. These noises usually sound like popping and backfiring. In some instances, your car’s engine might simply sound different than usual.
How do you adjust a Briggs and Stratton carburetor?
Locate the idle adjustment screw on the side of the carburetor. It sometimes has a spring wound around the shaft. Turn this screw clockwise with a Phillips screwdriver until you encounter resistance, which means it has contacted the carburetor seat. Back it off 1 to 1 1/2 turns.