Why Is My Generator Running Rough (5 Common Reasons!)

Home generators are a lifeline during power outages, providing the needed electricity to keep lights on, devices charged, and homes warm. 

But what happens when your trusted generator begins to run rough, disrupting the peace and quiet it once effortlessly provided? 

In this article, we will explore five common reasons why your generator might be running rough and provide helpful tips on how to rectify these issues.

Why Is My Generator Running Rough

Why Is My Generator Running Rough

1. Fuel Related Issues

Fuel-related issues are commonly caused by poor fuel quality, clogged fuel filter, or air in the fuel system

If the fuel has been sitting in the generator for a long time, it may have become stale and lost its volatility, leading to a rough running engine.


The solution to this problem includes draining the old fuel and replacing it with fresh fuel

The fuel filter should be checked and cleaned or replaced if necessary. If air is present in the fuel system, it should be bled out. 

2. Spark Plug Malfunction

The spark plug is a crucial component of your generator. It ignites the fuel within the cylinders to start your generator. 

A malfunctioning or worn-out spark plug often causes the generator to run rough. 

Spark plug issues can stem from various factors including dirty spark plugs, worn-out electrode, or incorrect spark plug gapping.

A faulty spark plug hampers the generator’s ability to burn fuel efficiently, leading to performance issues and rough running.


If your generator is running rough due to a spark plug malfunction, the first step should be to inspect the spark plug. 

Remove it from the generator and examine it for any signs of wear or damage. If the spark plug is dirty, it can be cleaned using a wire brush and some carburetor cleaner. 

However, if it’s damaged or severely worn out, replacement is the best option.

Remember to choose the right spark plug for your specific generator model. Incorrect spark plug selection can lead to further issues. 

Don’t forget to adjust the spark plug gap according to your generator’s specifications to ensure optimal performance.

3. Air Filter Blockage

One common reason a generator might run roughly is due to an air filter blockage. 

The air filter’s primary role is to sift out dust, dirt, and other airborne particles before they enter the engine. 

If this filter becomes blocked or excessively dirty, it can restrict the flow of air into the engine, leading to an imbalanced fuel-air mixture. 

This imbalance can cause the generator to run unevenly, often resulting in a rough or stuttering operation.

Remember, a dirty or blocked air filter can starve your generator’s engine of the air it needs to function efficiently. 

This blockage can lead to imbalances that may result in rough operation.


The solution to this issue is relatively straightforward – replace or clean the air filter. Regular checks and maintenance can prevent such problems from arising. 

If the filter is simply dirty, it can be cleaned using a proper cleaning solution and allowed to dry before being reinstalled. 

If it is damaged or excessively dirty, then it should be replaced with a new one. Depending on the type of filter used in your generator, you may also need to lubricate it during installation.

4. Carbon Buildup in the Carburetor

The main cause of carbon buildup in the carburetor is the incomplete combustion of fuel. 

During operation, small fragments of unburnt fuel lodge inside the carburetor and over time, these fragments solidify into a thick, sticky substance known as carbon. 

This buildup restricts the flow of fuel and air, leading to inefficient operation and causing your generator to run roughly.


To rectify this issue, the carburetor needs to be cleaned thoroughly. This usually involves removing the carburetor and using a carburetor cleaner to dissolve the carbon buildup. 

It’s important to remove all traces of carbon as even a small amount can lead to problems. 

Once the carburetor is clean, it should be reinstalled onto the engine and tested for proper operation.

5. Mechanical Wear and Tear

Over time, generators, like any other mechanical equipment, tend to deteriorate due to regular use. 

The components may wear out or get damaged, leading to rough operation. 

This is a common issue in older generators that have been in service for a long time without appropriate maintenance.


To address this issue, regular maintenance and timely replacement of worn-out parts is essential. It is advisable to schedule routine inspections with a professional service provider. 

If the damage is extensive, a complete overhaul or replacement might be necessary. 

Investing in quality parts and regular service can extend the lifespan of your generator and ensure smoother operation.


A generator that runs rough can be attributed to a variety of issues, ranging from fuel problems, spark plug issues, to more complex internal damage. 

Ensuring regular maintenance and timely repairs will prevent the generator from developing such problems. 

In all cases, if the issue persists or is beyond your skill level, it is recommended to seek professional help. 

Through proactive care and proper handling, the lifespan and efficiency of your generator can be significantly enhanced.


What are the common causes of a generator running rough?

Common causes include issues with the fuel system, spark plugs, or internal damage.

How often should I service my generator?

Regular maintenance is crucial; service it at least once a year or after 200 hours of use.

Can I fix a rough-running generator myself?

Some minor issues can be fixed at home, but for complex problems, it’s advisable to seek professional help.

What is the lifespan of a typical generator?

With proper care and maintenance, a generator can last up to 20-30 years.

Generator Not Producing Power

Briggs and Stratton Standby Generator Problems

Kipor Diesel Generator Light Blinking

Kipor Diesel Generator Not Starting

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top