14 Common Reasons Your RV Generator Won’t Start

RV Generator Won't Start

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It’s without any doubt that an RV generator is the most reliable source of electricity when boondocking.

Just hit the start button, and you have continuous power to run all your appliances.

However, things can become pretty frustrating if your generator doesn’t start when you need it the most.

You keep trying and trying, but nothing happens.

There can be an avalanche of reasons why your RV generator won’t start. 

Most of them are pretty easy to fix.

Here are the most common reasons why your RV generator won’t start:

  1. Old or Stale Fuel
  2. Oil Level is Low
  3. Wrong Choke Setting
  4. Low Fuel in Your RV
  5. Your Battery is at Fault
  6. Clean the Carburetor
  7. Faulty Spark Plug
  8. Clogged Air Filter
  9. Bad Fuel Filter
  10. Wrong Altitude Setting
  11. Weather is Cold
  12. Clogged Exhaust Pipe
  13. Rodents Destroyed the Cables
  14. Your Generator is Old

Read on; if you want to get your generator up and running to have a great camping trip.

But before we get to the reasons, let’s start with some basic troubleshooting.

Basic Checkup

Before you go on to the individual issues, a basic checkup may help identify and solve the problem.

Make sure this is where you start in your quest to find out why your generator doesn’t start.

Firstly, with portable generators, check if you have sufficient fuel in the tank. If your generator runs on propane, check to see if you have enough propane in the cylinder.

On the other hand, make sure your RV has enough fuel if you have an onboard generator. A built-in generator comes with a safety mechanism that prevents it from running if low fuel is detected.

Next, with sufficient fuel to run the generator, it’s time to see if the fuel valve and fuel tank cap vent is set to the on/open position.

Now, check if the choke is engaged as without the right choke setting your generator won’t start.

Next, make sure the economy mode or engine idle control is turned off.

Disconnect any load connected to the generator before startup.

Lastly, prime your RV generator appropriately before you try the ignition process.

These are the simplest things that can prevent your generator from starting. Make it a habit to perform a basic checkup every time you go to start your generator.

Why Won’t my RV Generator Start and How to Fix it?

There are many reasons why your RV generator does not start. 

Some are simple, and others are complicated.

In this section, we’ll look at the most common problems and how to fix them.

These are not the only reasons preventing your generator from starting.

But, they are a good starting point for troubleshooting the problem and in most cases will solve the issue.

Be it an onboard or a portable RV generator, we have you covered.

But, before you move on, there are two very important things to keep in mind.

  1. Generators produce electricity, so take proper safety measures before working on them.
  2. Don’t try anything technical if you’re unsure as it may damage the unit further and void its warranty.

Now, let’s take a look at the reasons your generator is failing to start and ways to fix them.

01. Old or Stale Fuel

Stale or degraded fuel is one big reason why your generator might not start. Fuel can go bad if the generator sits for a long time without use. 

This is especially true for portable generators that use gasoline and diesel. Portable generators that run on propane don’t have to worry about stale fuel issues.

Generally, gasoline has a shelf life of about 3-6 months, diesel about a year, and propane about 30 years.

Drain some fuel in a clean glass container to find out if the fuel in the tank has gone stale. When fuel goes bad it usually turns dark in color, smells sour, becomes cloudy, or has separations.

The Fix: Add Fresh Fuel

There is just one fix if your generator is not starting due to bad fuel. 

Drain the old fuel and add fresh fuel to the tank.

However, here are a few ways to prevent it from happening in the future.

  1. Buy a propane generator instead of gas or diesel
  2. Run your generator dry of fuel before storing
  3. Add fuel stabilizer to extend the life of your fuel

A good fuel stabilizer like the STA-BIL is a must-have for RVs with portable generators.

02. Oil Level is Low

Like your car, your generator needs engine oil to keep the moving parts lubricated. The oil reduces friction while preventing damage to the engine.

A drop in the oil level can hinder the normal working of the generator and may prevent your generator from starting altogether.

Like your car, your RV generator has an oil fill cap to fill oil into the generator. The cap has an internal dipstick that is used to check the oil level.

To check the oil level, unscrew the dipstick and wipe it with a clean cloth. Now dip it back into the oil fill chamber and take it out to find out your engine oil level.

The Fix: Add or Change Oil

Usually, generators use standard motor oil. However, some brands suggest a specific type of oil to be used in their generators.

Therefore, you need to check your specific model manual to find out the recommended oil to be used.

You can top off the oil if the level is low or change the oil if it looks dirty or darker in color.

Moreover, most modern generators come with low oil shutdown sensors. This prevents engine damage by preventing it from starting if low oil is detected.

You may want to disconnect the oil sensor to check if the sensor itself is malfunctioning.

03. Wrong Choke Setting

The choke is a regulator that controls the amount of air going into the carburetor. 

With the wrong choke setting, your generator will fail to start as there is too much or too little air mixed with fuel for combustion.

Depending on the type, model, and brand of your generator, the location of your choke lever may vary. However, in most portable generators, the choke lever is found just above the air filter of your generator.

The Fix: Adjust the Choke Lever

Before attempting to cold start or starting a generator that has been turned off for a few hours, move the choke lever to the closed position. 

To make things easy, the closed position of the choke is usually labeled as “start” in many generators.

Once your generator starts running, move the choke lever to the open or run position.

On the other hand, to restart a generator that was turned off not so long ago, position the choke lever halfway between fully open or close.

04. Low Fuel in Your RV

Low Fuel

Motorhomes with built-in generators use the same fuel the RV runs on from the same fuel tank.

As such, these generators come with a safety feature that prevents them from running if the fuel reaches a certain level.

Usually, about a quarter of a tank.

This ensures you have enough gas or diesel in the tank to start your RV and move out of the campground.

So, your generator may not be starting because you have reached your tank limit.

The Fix: Top Up Your Fuel Tank

Check your RV fuel gauge to find out how much fuel is left. 

If it is in the last quarter, visit your nearest gas station and top up your tank.

This should fix the problem.

If your RV generator does not start while having sufficient fuel in your tank, then you may want to check if you’re parked on a level surface.

Parking on an uneven surface or a hill may shift the fuel in your tank to one side. This will produce a false reading of your fuel level and prevent your generator from starting.

Make sure your RV is parked on an even surface before moving forward.

05. Your Battery is at Fault

Your onboard generator needs initial power to start the engine. The power is usually provided by either your chassis or house batteries.

If your generator doesn’t start, you need to check your RV battery system that the generator uses.

The Fix: Charge the Battery

Firstly, find out if your generator uses the chassis or house batteries to operate (check manual). Then, check if the battery has a sufficient charge.

If the charge is less, try charging the battery using another battery or your RV alternator using a jump cable.

Look for signs of any physical deformities, damage, or leaks. Check if the connections are in place and no wire is damaged.

Check for corrosion on the battery terminals as corrosion may prevent adequate connectivity. Clean it thoroughly with a metal brush.

Additionally, your battery will underperform during the winter seasons. So keep an eye on your battery system if it is too cold.

Keep in mind, with age and time, batteries wire down and will need to be replaced.

06. Clean the Carburetor

Portable RV generator owners who store their generators after a camping season with gas in the tank will face this issue.

As gasoline gets old, it becomes stale. Over time, the stale gas in the carburetor turns into a gum or gel-like substance.

This results in clogging your carburetor and fuel lines which prevents your portable generator from starting.

The Fix: Clean the Carburetor

To fix this issue, you need to clean your carburetor. This requires a bit of technical knowledge to carry out the carburetor cleaning process.

If you’re unsure, please call for professional help.

The carburetor may look different depending on your generator brand, model, but the process remains the same.

But before you start cleaning the carburetor, drain all the stale fuel out of your generator.

Follow the steps below to clean your carburetor:

  1. Turn off the fuel valve to prevent oil from pouring down from the tank
  2. Now, locate the fuel drain bolt at the bottom of the carburetor and drain the fuel from the carburetor
  3. Replace the drain bolt once all the oil is drained
  4. Now, remove the float bowl of the carburetor and clean it thoroughly with a carburetor cleaner
  5. Clean the main brass jet using a needle or a thin pin

With the carburetor clean, add fresh fuel and fire up your generator.

To prevent your carburetor from clogging in the future, make sure you run your generator dry before storage. Make sure to exercise your generator for an hour or two with a load every two weeks if you store the generator with fuel in it.


07. Faulty Spark Plug

The primary function of a spark plug is to ignite the fuel and air mixture in an internal combustion engine. Without ignition, your generator engine will never start; forget running.

A spark plug may not be functioning properly for a few reasons, like:

  1. The cable connecting to the spark plug is loose or damaged
  2. The carbon deposit on the head is preventing it from creating sparks
  3. Your spark plug is old and needs replacement

The Fix: Check Cable, Clean, or Replace

First, check if the power cord connected to your spark plug is not damaged. Now, check the cable for a loose connection.

Once your spark plug passes the first test, it’s time to check for sparks.

You can do this in two different ways: 

  1. Using a spark plug tester 
  2. Remove the spark plug and test it manually

Using a spark plug tester is the easiest. All you have to do is connect your plug tester to the spark plug and pull the recoil start. If the spark plug is in working order, you’ll see light glowing on the tester.

To test the spark plug manually, you need to remove the spark plug using a spark plug wrench. Once removed, check the plug head for carbon deposits or broken electrodes.

If there are deposits on the head, clean it using a knife or brush. If you have a broken electrode, then you’ll have to replace the spark plug.

To test the spark plug, take it close to the engine crankcase with the power cord connected. Now, pull the recoil start, and look for bright blue sparks.

If you see bright sparks, then you have a good working plug that wasn’t functioning properly due to carbon deposits. However, if you don’t see any sparks, then you have a bad spark plug and need to replace it.

08. Clogged Air Filter

Your air filter is most likely choked if your generator doesn’t start after you have adjusted the choke setting.

The main function of the air filter of your generator is to make sure the engine breathes clean air.

With time and use, the amount of air passing through the air filter will diminish due to the accumulation of dirt and debris. Moreover, if you have been camping in an area with a lot of dust in the air, the air filter will quickly jam. 

This will prevent sufficient air from entering the carburetor, thus hindering ignition and combustion.

The Fix: Clean or Replace the Air Filter

To clean the air filter, open the air filter housing and take out the sponge filter. Simply, wash the sponge filter using soap and water if it looks dirty.

Air-dry the filter before putting it back into the housing.

Replace the sponge air filter with a new one if the filter looks worn or broken down.


09. Bad Fuel Filter

Every generator uses a fuel filter that cleans the fuel before it reaches the engine for combustion.

Over time, your fuel filter will get clogged due to the buildup of debris from the fuel.

When this happens, you’ll have difficulties starting the generator since there is less to no fuel going to the engine.

This is why you need to replace or clean your fuel filter at least once a year.

The Fix: Replace your Fuel Filter

Most portable generators use in-line fuel filters, meaning the fuel filter is on the fuel line between the tank and carburetor. The location and type of your fuel filter may vary depending on the brand, type, and model of your generator.

Check the user documentation of your generator to find out more.

Here are the steps to replace an inline fuel filter:

  1. First, shut off the fuel valve to prevent fuel leaking when you remove the fuel filter
  2. Now, remove or loosen the clips on both ends of the filter with nose pliers or a screwdriver.
  3. Slide-out the old fuel filter and slide in the new one
  4. Reconnect the metal clips securely
  5. Turn on the fuel valve and check for leaks

10. Wrong Altitude Setting

Your generator’s engine needs the right proportion of air and fuel mixture to start and run properly.

This balance can be put off if you camp high above sea level (above 5000 feet). 

As you go higher above sea level, the air gets thinner, resulting in a lower oxygen level. This creates an imbalance between the fuel and air ratio, preventing your generator from starting or running properly.

The Fix: Adjust to the Right Altitude Setting

Most onboard generators come with an altitude adjusting dial that hands you the ability to choose the right altitude setting easily.

Check your generator’s user manual to find out its location and the right settings.

However, it’s a bit complicated with portable generators. You may need to remove the carburetor to rejet or replace the old jet with a new appropriate jet.

Rejetting a portable generator is not the most difficult task. However, if you’re unsure, call for professional assistance.

This video illustration will give you an idea of how to install the high altitude main jet in a portable generator.


11. Weather is Cold

Both onboard and portable RV generators will have difficulties starting as the temperature drops.

The drop in the outside temperature (below 40F) will freeze the cylinder making it difficult to move when you try the ignition process. Due to such low temperatures, the fuel can’t produce the vapors needed for combustion, thus preventing ignition.

Additionally, as the temperature drops, the viscosity of the engine oil increases, and the battery refuses to work resulting in a camping generator that won’t start.

The Fix: Keep the Generator Warm

The simplest trick to make sure your generators start even during the winter months is to keep them warm.

Make sure you don’t leave the generator outside during winter. Use a cover or keep the generator in a well-insulated box when not in use.

You can also use a block heater or a normal heater to heat the engine before you attempt to start your generator.

Additionally, make sure the choke is fully closed before you try to cold start the generator.

12. Clogged Exhaust Pipe

Your RV generator will not start if the exhaust pipe of your generator is blocked.

The exhaust system expels the gases produced during combustion in an internal combustion engine. With a blocked exhaust pipe, there is no place for the gases to go, but, back to the combustion chamber.

The exhaust pipe of a camping generator can get blocked due to outside debris entering the pipe or carbon buildup.

This prevents combustion as no fresh air can enter the combustion chamber, resulting in your generator not starting or running.

The Fix: Clean the Exhaust Pipe

First, with a torch, inspect the inside of your exhaust pipe to find if there is debris.

To clean the exhaust pipe, use a long metal wire with a small piece of cloth tied securely to the end entering the pipe. Apply some degreasing spray on the cloth and slowly scrub the inside of the pipe.

Repeat the cleaning process until the blockage is removed.

13. Rodents Destroyed the Cables

Rats and other rodents are well known for chewing away electric wires and pipes. Damaged wires and pipes will prevent your generator from starting.

However, fixing your damaged wires and pipes will not solve the problem as your friend will return for more.

The Fix: Get Rid of the Rodents

At first, you need to find if you have a rat/mice living where you store your portable generator or in the onboard generator compartment.

In the case of the onboard compartment, remove the rat’s nest and block all the gaps that are big enough for the rats to get in and out with copper mesh.

This copper mesh is designed especially for rats and they will not be able to break it.

On the other hand, if you have rats or mice in your garage, make sure you get them using a rat trap or a rodent repellent.

14. Your Generator is Old

With use and time every machine wires down to an extent beyond repair. Through the wire and tear of your generator can be slowed with proper maintenance.

But, eventually, you’ll have to replace your old generator.

The Fix: Buy a New Generator

If you have been using your existing generator for a long time, then chances are the wire and tear have taken their toll. Thus, your generator is giving you so much trouble.

It’s time you treat yourself with a new generator. Newer models have lots of advantages over older models.

They are quiet, fuel-efficient, produce clean power, and most importantly will run without giving you a lot of trouble.

Diagnose, Repair, or Replace

Generators are essential to provide the necessary power to keep you and your family comfortable when camping in the wild.

But, things can get very unpleasant if your RV generator doesn’t start when you need it.

Don’t panic if your generator doesn’t start as the reasons we spoke about above are the most common issues and are easy to fix.

Remember, proper maintenance is the key. With proper upkeeping, you can keep your generator in the top running order.

If however, the problem is beyond your reach, call for professional help.

If nothing works, then a new portable RV generator is your only option.