Your question: What causes lawnmower engine to surge?

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.

Why does my lawn mower 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.

Why does my lawn mower rev up and down?

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 does engine surging mean?

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. Misfiring happens when one of the cylinders of an engine’s combustion cycle fails.

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.

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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.

Why is my lawn mower not running smoothly?

Causes: If the engine starts, but does not run smoothly, it means that the spark plug and ignition system are in order and you need to look elsewhere for the source of the problem. The usual culprit is air intake or fuel system related.

Why does my lawn mower run sluggish?

Maintenance lapses become evident when the mower turns over slowly or begins to falter at start-up. The fault could be a dirty spark plug, air filter or carburetor, or it could be related to the quality of the gasoline used. Slow starting can also be the result of a failure to clean the blades.