What Causes A Lawn Mower To Surge

Lawnmowers are a staple of outdoor maintenance. Keeping a lawn in order requires regular mowing, and it is important that the right tools are used to do so. When something goes wrong with a lawnmower, it can be difficult to determine the cause; this article will discuss what causes a lawnmower to surge.

Surging is an issue where the engine runs erratically, causing fluctuations in power output as well as uncomfortable vibrations for the operator. This problem can stem from several different sources and should not be taken lightly; if left unchecked, surging can lead to serious damage to both your machine and its user.

Fortunately, by understanding what causes these issues one may take steps towards preventing them before they occur.

What Is Lawn Mower Surging

Lawnmower surging can be a frustrating issue, leading to an inefficient cut and potential damage. It is often caused by worn spark plugs, jammed blades, low compression, overfilled tanks or incorrect tire pressure – all of which reduce the performance of your mower.

Imagine having to tame a stallion that has been spooked; similarly, with lawn mowers we need to take control before it gets out of hand.

The first port-of-call should always be checking for any visible obstructions in the cutting deck, as these may be causing jamming issues under the hood. If no blockages are present then testing each component individually will help narrow down the cause – start with spark plugs and work through the list until you find what’s causing the surge.

With simple tools and some patience you’ll soon have your machine running like a dream again!

Clogged Carburetor

A clogged carburetor is one of the most common causes of lawn mower surging. This occurs when dirt, debris, and gunk build up in the fuel lines and reduce the flow to the engine. Without a steady stream of clean gasoline, an engine will struggle to maintain its power output, causing it to surge as RPMs fluctuate unexpectedly.

Other potential reasons for this problem include a clogged gas line, broken spark plug or faulty spark plug connection, air leak from worn parts such as gaskets or seals, and insufficient fuel pressure due to blockages in fuel filters.

In order to diagnose the true cause of your lawnmower’s surging issue, you should inspect all these components carefully. Diagnosing these issues accurately can help prevent further wear-and-tear on internal engine components while also ensuring that your mower runs at peak efficiency.

Faulty Ignition System

The faulty ignition system is the most common cause of a lawnmower surging.

When there is an issue with this system, it will often result in irregular engine speed, as well as backfiring and stalling.

To ensure that the correct spark plug gap is maintained for optimal performance, all components must be checked thoroughly – from fuel pump to fuel lines and choke valve to oil filter.

Ignition problems can also occur due to loose or corroded electrical connections or worn out parts such as spark plugs or coils.

If these issues are not addressed properly, the surging may continue even after other repairs have been made.

Therefore, it’s important to diagnose and repair any faults in the ignition system before attempting other solutions.

The bottom line: a thorough inspection of your mower’s ignition system should always be done first when attempting to resolve surging issues.

Dirty Air Filter

The air filter of a lawn mower is an integral part of the mower’s system, and if it has become clogged or dirty, it can cause surging.

This usually happens when operating in muddy terrain, or with wet grass that kicks up debris.

In addition to this, stale fuel or air leaks could be causing the issue as well, which further complicates matters.

The exhaust should also be checked to ensure it isn’t clogged; otherwise, there may not be sufficient airflow for proper operation.

All these components must be inspected thoroughly before any potential repair work is done to avoid unnecessary complications.

Careful attention must also be paid so that no dirt enters the engine during maintenance which could potentially damage its parts.

Taking all these factors into account will help identify what is causing the surge and how best to resolve the problem.

Incorrect Mixture Of Fuel And Oil

One of the common causes for a lawn mower to surge is an incorrect mixture of fuel and oil.

An uneven spark plug gap, corroded fuel lines, or faulty fuel pump can all cause air flow issues that lead to surging.

Additionally, too much oil in the engine can cause clogged components or stuck float valves which will also result in inconsistent performance.

To ensure optimal performance from your lawnmower it is important to regularly check these parts and keep them clean and free of debris so they are functioning correctly.

Regularly replacing the fuel filter and checking the spark plugs should be part of any preventative maintenance routine.

Taking precautionary steps like this will help maintain consistent power output from your mower’s engine, as well as preventing future problems with surging.

Frequently Asked Questions

How Do I Adjust The Mixture Of Fuel And Oil In My Lawn Mower?

When it comes to lawnmower repairs, one of the most common causes of surging is an incorrect mixture of fuel and oil. To ensure that your machine runs smoothly, you will need to adjust this ratio accordingly.

Before doing so, however, check for any clogged spark plugs or fuel lines as well as a dirty fuel filter or faulty ignition switch. If these components are not functioning properly, they can contribute significantly to your engine’s surging behavior.

How Often Should I Clean My Lawn Mower Carburetor?

Lawnmower Repairs Expert here to help you with your lawn mower carburetor maintenance. It’s certainly an arduous task, but one that will pay dividends in the long run!

Depending on usage and environmental conditions, cleaning/servicing your carburetor should be done every 50 – 150 hours of operation – or at least once a season.

This involves removing the spark plug, draining fuel from the tank, disconnecting any fuel lines and filters, and taking off any oil filters.

As always: safety first! Follow the manufacturers instructions for proper disposal of all components removed before beginning repairs; otherwise it may cause a surge of unwanted consequences.

How Do I Test The Ignition System On My Lawn Mower?

When testing the ignition system on a lawn mower, an expert should begin by examining the spark plug for any signs of wear or damage.

Next, they may check the fuel pump to ensure that it is providing adequate pressure and flow.

If there is an electric starter, this should be tested as well; however, if the mower has a choke lever, then it should also be checked for proper operation.

Last but not least, air flow must be examined to make sure it’s able to reach all areas in need of combustion.

All these components are integral parts of a working ignition system and help ensure that your lawn mower runs smoothly and efficiently.

What Kind Of Air Filter Should I Use For My Lawn Mower?

Choosing the right size air filter for your lawn mower is like finding a needle in a haystack – it can be an overwhelming task.

As an experienced Lawnmower Repairs Expert, I encourage you to take control of this situation and understand exactly what you need to do in order to select the correct size air filter for your machine.

It’s essential that you check fuel quality, change spark plugs and replace air filters regularly to ensure optimal performance. Additionally, maintaining carburetors and clean hoses will help prevent surging issues from developing.

So don’t wait until its too late; make sure you have the right air filter for your lawn mower today!

How Do I Know If My Lawn Mower Is Surging?

Lawnmower repairs expert may help you diagnose why your lawn mower is surging.

The most common causes of lawn mowers surging are clogged fuel lines, air intake leaks, spark plug issues, fuel contamination or improper lubrication.

If the engine revs up and down while running then this could be a sign that it’s either not getting enough fuel or too much air entering the system.

It is important to check all components of the machine for any signs of damage or wear before attempting to repair anything on your own.

This can include checking for any loose parts in the carburetor as well as inspecting the fuel line and spark plugs for dirt or debris buildup which can inhibit proper functioning.

Additionally if there is any evidence of fuel contamination such as discoloration present then this should also be addressed prior to attempting repairs.


Lawnmower surging is a common issue, yet can be easily rectified. In order to prevent and solve this issue, it is important to have knowledge on the basics of lawnmower repair and maintenance.

This includes understanding how to adjust the fuel-oil mixture, clean carburetors regularly, test ignition systems, install air filters correctly, as well as being able to identify when your mower is surging.

Moreover, if you are unable to resolve your mower’s surge issues after following all of these steps, then professional assistance may be required. An experienced technician will be able to diagnose and fix any underlying causes that could potentially harm your engine or cause more serious damage in the future.

Therefore, with proper care and attention given to your mower’s components, you can avoid the risk of having an unresponsive machine during those crucial moments where time matters most. With just a few easy steps, you can ensure that your lawnmower remains running smoothly for years to come!