What causes lawn mower engine surging?

How do I stop my lawn mower from surging?

A thin coating of engine oil on foam filters typically helps them attract dirt that could end up in your carburetor. Paper filters, however, only use their pleated medium to catch dirt and dust. An air filter is a quick fix that should be your first stop when troubleshooting a surging lawn mower.

What makes a lawn mower surges up and down?

Carburetor Adjustment

A carburetor that’s incorrectly adjusted is a common cause of poor engine idling that results in hunting and surging. Fortunately, most lawnmowers have two screws that allow you to adjust the carburetor yourself. One screw controls the idle speed while the other adjusts the idle mixture.

Why does my lawn mower rattle?

One of the most commonly experienced noises from a lawnmower is a loud rattling sound resulting from a loose blade assembly. If the blade assembly is loose, it will move around during startup, and it will keep on rattling as the lawnmower runs.

Why is my Toro lawn mower surging?

Surging is always caused by a weak air:fuel ratio. This can be due to a lack of fuel ( blockage ) or excess air ( leak at manifold ). Actually cleaning / replacing the air filter usually makes surging worse. You can start at either the carb or the fuel tank and check for obstructions.

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How do you adjust the governor spring on a lawn mower?

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.

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 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.

What is engine hunting and surging?

The most common cause of engines ‘hunting or surging’ is stale fuel evaporating, leaving residue on the main jet or dirty fuel causing partial blockage of the jet. If the motor runs smoothly on partial choke, this usually indicates main jet restriction.

Why does lawn mower engine pulsate?

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.

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Can bad spark plugs cause engine 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.