Often asked: What Causes Lawn Tractor Engine To Surge?

What causes a small engine to rev up and down?

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. To fix this type of problem, check the air filter to ensure that it’s not clogged with dirt and debris.

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.

What does engine surging mean?

Engine surging is different from a difficult start or a no-start problem. “ Surging ” does not refer to a knocking engine or one that idles rough or stalls. Engine surging is when an engine starts easily and accelerates smoothly, however after a few minutes at a steady speed, it either surges in speed or misfires.

What causes a snowblower engine to surge?

If the snowblower engine RPMs are surging up and down, check the following parts for damage: springs, gasket, carburetor, and spark plug. There are springs on the carburetor that allow the butterfly valves to open and close properly. The springs also ensure the governor is operating properly.

What causes a carbureted engine to surge?

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.

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.

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.

How do you adjust the governor on a Briggs and Stratton engine?

To adjust the governor, you would loosen the screw on the bottom of the governor arm and push the governor arm so the throttle is wide open. Then you would turn the bottom “clip” (which is connected to the governor shaft) counter clockwise. This will set the governor shaft on top of the governor spool.

Why is my riding mower sputtering?

Your mower pulls in air from outside and mixes it with gasoline for the proper explosion inside the engine. A dirty air filter inhibits the flow of air into the carburetor. Clean or replace the air filter to stop the mower from sputtering to a halt. Too much air can also cause problems for the engine.

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 does engine surging feel like?

You may notice the tachometer fluctuating, for example, from 1500 to 2000 rpm. At the same time, you may feel a soft and rhythmic jerking motion. The problem may come from a faulty sensor or system that is making the computer deliver too much or too little fuel, and then try to correct the fault by over-compensating.

Can a bad O2 sensor cause surging?

Surging is among the many problems a failing O2 sensor can cause, but it isn’t the only one.