Why Generac Generator Won’t Start? 8 Reasons with Solutions!

Although Generac is a very well-reputed brand for generators, it can also show some problems from time to time that require repair. 

So, why Generac generator won’t start?

The Generac generator won’t start if it has low or contaminated oil in the tank. Change the oil with fresh ones and refill to the appropriate level. A dirty or clogged carburetor, fuel, and air filter can also cause the generator not to start. Clean or replace these components to fix the issue. A faulty spark plug, ignition coil, and battery can also cause this issue that requires replacing. 

Read this article to have a proper idea to solve this problem.

8 Reasons Why Generac Generator Won’t Start?

generac generator won't start in cold weather
Source: midwestgeneratorsolutions.com

Before discussing what would cause a Generac generator not to start, have a look at the reasons from this table. 

Low Oil LevelRefill the oil
Old or Contaminated OilReplace the oil 
Dirty CarburetorClean the carburetor
Plugged Fuel & Air FilterReplace the fuel and air filter 
Bad Spark PlugReplace the spark plug 
Bad Ignition CoilReplace the coil
Bad Starter Recoil Replace the starter recoil 
Bad battery Replace the battery 

Reason 1: Low Oil Level

When the Generac generator doesn’t start, the most common reason is low oil level as the fuel tank of this generator is very small. 


Check the oil level of your Generac generator and fill up the tank as required. The manufacturer suggests using Generac 5W-20 GEO Full Synthetic Oil for Generac generators. 

If refilling the oil is not possible at this moment, you can bypass the oil sensor for now. Remember, this solution is temporary. 

Reason 2: Old or Contaminated Oil in the Tank

Even though the fuel tank is full, if the tank has contaminated or old oil, it can cause the Generac generator not to start. 


When you are using the generator for the first time, you have to change the oil after 20-30 hours of operation. And after that, you must change the oil every 100 hours of operation. 

You should also replace the oil if you start the generator after a long time

Reason 3: Dirty Carburetor

When the carburetor is dirty it restrains the gas from mixing with air and as a result, the combustion process doesn’t start. 


Clean the carburetor of your Generac generator by removing it. Use a good Carburetor cleaner to thoroughly clean the fuel jets, carburetor float, and float needle.

Reason 4: Plugged Fuel & Air Filter

A plugged fuel filter in the Generac generator causes less fuel to enter the engine, thus the generator doesn’t start. A clogged air filter can also restrain the generator to start. 


Replace the oil filter of the Generac generator every two years or 200 hours intervals. And replace the air filter every 4 years or 400 hours of operations. 

Reason 5: Bad Spark Plug

If the spark plug is dirty, the electrode is cracked, or the porcelain is broken, it can cause the generator not to start. 


Remove the spark plug and clean it properly if it is dirty. If found broken, you have to replace the spark plug

Reason 6: Bad Ignition Coil

If the ignition coil of the Generac generator is faulty, it can cause the generator not to start. 


Check the ignition coil with an ohm meter. If you find any restriction in the continuity of the coil, you have to change the ignition coil. Check the following video to change it.

Reason 7: Bad Starter Recoil

If the starter coil of your generator is worn out or broken, it causes the pulley and springs to become unstrung. As a result, the generator can’t get started easily. 


Replace the starter recoil and restring it properly. You can also just change the broken parts of the starter assembly but in most cases, the pricing of doing so is almost the same as replacing the whole thing. 

Reason 8: Bad Battery

If you are thinking, Why won’t my Generac generator start just clicking, it is because your generator has a bad or dead battery. 


Check the battery connection to the generator. If the age of your generator battery is 3 or above, you must replace it. You can follow the following video to replace the battery.

If your Generac generator doesn’t start even after addressing these common reasons, you have to troubleshoot the following problems as well. 

  • Check the Spark Arrestor and if the screen is dirty or clogged, you have to replace the screen. 
  • If you hear a clicking noise when you try to start the generator, but it doesn’t start, that means the starter solenoid is faulty and you must replace it. 
  • Remove the fuel cap and try starting the generator. If it starts, the fuel vent of the cap is faulty and needs to be replaced. 
  • Check the fuel line, if required remove it and clean it with the carburetor cleaner. 
  • Check the ignition switch and if required, replace it. 
  • Have the choke dial checked by a mechanic and replace it if necessary. 


Here go all the reasons why Generac Generator Won’t Start with their appropriate solution. Following the instructions should help you repair the generator in no time. If you are not sure how to do it, please consult a mechanic. 

That’s all for now. All the best and goodbye!

Frequently Asked Questions (FAQs):

How Long Is A Generac Warranty?

You will get a 5-year of standard warranty with 7-10 years of extended warranty on some parts in a standby generator. And for portable Generac generators, the warranty is 2-3 years depending on the generator model. 

What Causes The Generator To Start And Stop?

The wrong oil level on the generator causes it to start and stop after some time. If the oil level is too low or too high, it increases the temperature of the oil too quickly and causes a shutdown. 

What Are The Alternatives To Generac Generators?

Briggs & Stratton and Champion generators are the closest alternatives to a Generac generator. Also, Honda and Predator generators can be a great alternative to a Generac generator.

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