How Much Does It Cost to Repair a Generator?

Typical Range:

$171 - $394

Find out how much your project will cost.

Cost data is based on actual project costs as reported by 1,373 HomeAdvisor members. Embed this data

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Updated July 25, 2022

Reviewed by Salvatore Cutrona, Angi Expert Review Board member and founder of Cutrona Electric, LLC, in Sherman, CT

Written by HomeAdvisor.

The average cost to repair a generator is $273. Maintenance of portable or smaller (7 to 10 kW) models will typically be less expensive, costing around $50. On the other hand, larger (30 to 45 kW) models cost as much as $700. The typical range for this project is between $171 and $394 and will depend on whether you have a portable or standby generator.

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National Average $273
Typical Range $171 - $394
Low End - High End $85 - $700

Cost data is based on actual project costs as reported by 1,373 HomeAdvisor members.

Average cost to repair a generator is $300, ranging from $50 to $700

Generator Repairs by Type

Large and small engine generator repairs typically cost between $200 and $400, while portable generator repairs cost about $50.

Portable Generator Repairs

Repairing a portable generator usually costs around $50. Less powerful than other generators, portable units are suitable for powering a couple appliances in your home for a few hours. They require a lot of fuel, and you must keep them full to keep them working. Repairs for these units cost less than fixing permanent standby generators because they are less complex and take less time to diagnose and fix. You can troubleshoot many common issues yourself.

  • Overload: These styles can only provide a certain amount of energy. Many homeowners overload them and compromise the system. If a generator isn't working, try disconnecting an appliance or two.

  • Fuel and Oil Problems: You have to monitor these units and frequently fill their oil and fuel. A system that isn't starting or shuts down during operation could be low on either. It could also be that the fuel has degraded from disuse.

  • Overheating / Lack of Air: It needs proper ventilation to continue operation. A clogged filter could cause the system to stop mid-operation or refuse to start.

  • Loose or Bad Spark Plugs: If you're having difficulty getting it started, you may need to tighten or replace the spark plugs.

Standby: Large & Small Engine Generators

It typically costs around $600 to repair a standby generator. These units are permanent fixtures that connect to a natural gas or propane line. Some will sustain a few appliances, while others can power your entire home if necessary. You may encounter many of the same issues you'd encounter with a portable unit. Still, some issues are unique to this type:

  • Overfilled Tank: This is one of the most common mistakes homeowners make, according to service professionals.

  • Battery Failure: Sulfate builds up on the battery plates and minimizes the current. You will have to replace a battery with too much of this buildup. Experts recommend doing so once every three years. Connections can also loosen or collect buildup, causing battery failure.

  • Carburetor Clog: Failure to start and poor operating performance are signs that the carburetor is clogged. This is an expensive fix because it requires that a professional disassemble the engine.

  • Spark Plugs: As with portable units, bad spark plugs are common with standby equipment.

  • Leaks: This equipment can leak coolant, fuel, and oil. Fuel will leak when it isn't being used to its full load capacity. Coolant will leak from the block heater hoses if the hose material cannot handle the temperature.

  • Breaker/Switch Issues: Human error is a common culprit in generator operation. If you leave the control switch in the off position or the breaker is left open, the equipment won't work. The breaker can also trip in a storm or outage.

  • Gauge Malfunction: The fuel gauge can get stuck during disuse and give inaccurate readings.

  • Air Pockets: Air can get into the tank during disuse. Injectors often fail to fire if there are bubbles in the system.

  • Coolant Problems: It is common for these generators to have issues with coolant levels and temperatures. Low levels could indicate a leak, while low temperatures could signal faulty block heaters.

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Generator Repair Cost Factors

Generally, there are three main factors affecting the cost of generator repair: the fuel type it uses, its size, and the scope of the repair.

Fuel Type

Each fuel type comes with its own repair and maintenance schedule:

  • Propane: These generators cost more to fix and maintain, but demand for these services will be infrequent. These units don't have a lot of issues because there are fewer components involved in their operation. Propane's longer shelf life also means that the fuel won't need to be managed or removed during disuse.

  • Natural Gas: Will require more involved and costly installation. But once connected, maintenance should be your only concern. Repairs are infrequent.

  • Gas and Diesel: Require more upkeep and repairs. These fuels have short shelf lives and can clog or degrade during disuse. Spills and overfilling are common problems.


Generators come in different sizes, denoted by kilowatts. Small models typically deliver 7 to 10 kW, mid-size models are 12 to 20 kW, and larger ones deliver 22 to 45 kW. Larger models are much more complicated, and the cost of fixes will be higher. The small and less powerful the generator, the less the cost of repairs will be.


The problem you're having with your generator will ultimately determine the cost of repairing it. If it's an issue with your electrical meter or power panel, you'll need to hire a licensed electrician, increasing the cost. If it's a problem with your fuel tank, you might need to contact your local utility company to check the connection to your fuel line.

Generator Maintenance and Services Prices

Even when your generator doesn't break down, it requires periodic maintenance. If you live in a cold climate, annual tune-ups should be part of your winter storm preparedness strategy.

Your unit will run periodically, which preserves energy and makes regular maintenance more important. Part of your consideration should always be your generator power consumption and safety.

When you hire a service contractor for generator maintenance, expect service on the following systems:

  • Lubrication

  • Cooling

  • Fuel

  • Air and combustion

  • Battery/starting mechanism

  • Transfer switch

  • Alternator

  • Engine filter

Generator Service Cost by Type 

The size and type of generator in your home can change the extent and cost of maintenance. The table below is based on average run time; it might require more frequent maintenance if your generator runs longer than average.

Larger, commercial generators typically run more frequently than units designed for smaller homes. As a result, they will need more frequent and more thorough inspections and maintenance. Industrial products should be serviced monthly, thoroughly checking all components. Hiring a pro is crucial to make sure everything checks out during the inspection regardless of unit size.

Annual Service Contracts

Unlike warranties, these agreements cover necessary maintenance. Annual service contracts typically cost between $100 and $300 per year and are commonly offered through the generator manufacturer.

Some installation professionals might also offer their own annual maintenance contract. Talk to your installation and repair professionals for more details because these agreements vary in service and price.

How Much Does Generac Generator Maintenance Cost?

Like other brands, Generac generators require annual maintenance. Generac offers a $200 annual service contract that takes care of the yearly checks, but some professionals offer less expensive options at $80 to $150 per checkup. If your generator is still under warranty, work only with the manufacturer or approved contractors to prevent voiding its coverage.

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Generator Warranties 

Most models come with warranties that include service if something goes wrong. These warranties do not cover the regular maintenance and tuneup required. While warranties differ by individual product, here's what you can expect from the major generator brands:

Length of Generator Warranties
Brand Default Length (in years)
Generac 2
Craftsman 2
Kholer 5
Coleman 5
Briggs & Stratton 5

Generator Rewind

Because of the difficulty of rewinding a generator motor, leave it to an experienced professional. Most pros will charge between $300 and $700.

Electric motors periodically need rewinding to ensure reliable and efficient operation. The process includes removing the old coil, winding a new coil onto the motor, and varnishing the coil to make it permanent.

Cost of Fixing or Replacing Home Generator Parts

In most cases, your generator stops working because of a specific part. Diagnosing and repairing that part is more beneficial and cost-effective than a complete generator installation cost. In some cases, complete engine repair could send your budget into the thousands.

Generator Part Repair Cost
Stator and Rotor $300 – $1,500
Carburetor $50 – $300
Engine $50 – $2,000
Voltage Regulator $40 – $80
Transfer Switch $50 – $200

Stator & Rotor

A new stator and rotor set typically costs between $300 and $1,500. They are stationary and rotating parts of any system that generates electricity. When they stop working seamlessly, they need repair or replacement. 


The carburetor mixes air and fuel to create the right combustion ratio. Small problems, such as a loose gasket, can be easily repaired for less than $50. Complete carburetor replacement will cost between $100 and $300.


The engine is the most important component of the unit. Repairing small parts of your generator's engine can cost as little as $50, but more comprehensive jobs can be more than $2,000.

Voltage Regulator

Especially when connecting major appliances to your generator, the voltage regulator is crucial. A new part costs between $40 and $80, plus the required cost to hire an electrician.

Transfer Switch

Repairing an existing transfer switch will typically cost between $50 and $200, depending on the exact problem. If the problem is significant, consider paying to replace the transfer switch, which will be between $200 and $400 plus three to four hours of electrical labor. 

Who Repairs Generators? DIY vs. Pro Repair Shops

Repairing your home generator almost always requires a professional. This advanced electrical equipment will require expertise to diagnose the problem and repair or replace the right parts. Reserve DIY generator repair kits for small issues and routine maintenance.

Read reviews and get quotes from experienced generator repair services in your area.


How long is a generator supposed to last?

The lifespan of a generator varies depending on the type and size, but you should get between 1,500 and 3,000 hours out of one. Standby generators generally last longer than portable ones.

Can a generator run 24 hours a day?

It's best not to run a generator for more than 24 hours and less than 12 hours if you can help it. If you run it continuously for more than a day, excessive heat can build up that could damage the engine.

Can you put too much gas in a generator?

Never completely fill the fuel tank in a generator because it can overflow and spill onto the hot engine, resulting in a fire. Fuel can expand in the tank, so you should give it room to do so.

Where do you store a generator when not in use?

When not using a generator, store it in a cool, dry location, such as a clean shed or garage. You can store it outside as long as you properly cover it, but it is always best to keep it as protected from the elements as possible.

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