Onan 5500 Generator Won’t Start – What To Do?

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Onan 5500 generators are quiet and efficient. However, what could cause this problem if it won't start, and how do you troubleshoot it? We have done the research to help you get your generator running again.

If your Onan 5500 generator doesn't start, you should try to prime it. If this doesn't work, then it could be due to the following:

  • Low Oil
  • Low Fuel
  • Bad Fuel Valve
  • Clogged Carburetor
  • Bad Spark Plugs
  • Bad Oil Sensor
  • Dead Battery
  • Clogged Fuel Filter
  • Bad Ignition Coil
  • Faulty Recoil Starter
  • Bad Safety Switch
  • Faulty Fly Wheel Key
  • Bad Start Switch
  • Bad Voltage Regulator
  • Fuel Leak

No matter what you are using your generator for, it is important to start whenever it is needed. In this article, we will take a look at the reasons why your Onan 5500 generator isn't starting. In addition, we will discuss and answer other frequently asked questions, so read on!

Installing a whole house emergency generator, Onan 5500 Generator Won't Start—What To Do?

Onan 5500 Generator Won't Start—What To Do?

If your Onan 5500 generator doesn't start, you should try to prime it. Priming a generator helps get the fuel flowing so that the engine can start.

If priming the generator doesn't solve your problem, then it could be due to the following:

Low Oil

If the oil level is low, you should have it checked out immediately by an authorized Onan dealer. If your generator runs out of oil while running, it can damage its piston rings and other components. The result would be that the oil will leak into the carburetor, which could also cause further problems.

Low Fuel

A common reason your generator won't start is due to low fuel. Check that you have sufficient fuel to start your Onan 5500 generator. If the fuel level is adequate, then go to the next step.

A man pours gasoline into a generator on the doorstep

Bad Fuel Valve

If the fuel valve is bad, it won't allow fuel to flow into the carburetor. This means that the engine also won't start. Make sure that you check it and replace it if needed. You can do this by disassembling and cleaning it, and inspecting for damage. If there is no damage, put it back together and replace it if needed.

Clogged Carburetor

A clogged carburetor will stop the generator from starting. You can clean out your carburetor by closing the fuel valve and removing the bowl at the bottom. You can also try using an air compressor to blow out any debris that might be blocking the channel to fuel.

Bad Spark Plugs

If your spark plugs are bad, they won't provide the necessary electrical charge needed for starting. You can tell if the spark plugs are bad by taking them out and checking for damage or burns. If they are burned, you should replace them immediately.

Bad Oil Sensor

If the oil sensor is bad, it can mean that too much oil goes into the engine, preventing it from starting. Make sure to check the level of your generator's oil. If it is too much, it will have to be drained.

Dead Battery

A dead battery can cause problems that range from not being able to start the generator or powering on but not being able to stay powered on. The best way is to check the battery level and make sure that you charge if needed. If there are any cracks, you should replace them right away.

Clogged Fuel Filter

If the fuel filter is clogged, then it will cause your generator not to stay powered on for more than a few seconds or minutes. This can be easily checked by taking out the old one and replacing it with new fuel filters.

Bad Ignition Coil

The ignition coil provides the spark needed for the engine to get the fuel mixture ready. If this component is bad, it can prevent your generator from starting. Make sure to check this and make sure that it is not damaged in any way and replace it if necessary.

Faulty Recoil Starter

If the recoil starter is faulty, it will not allow your generator to start because you will not be able to pull hard enough for combustion. Therefore, you should ensure that there is no damage to the starter and replace it if necessary.

Bad Safety Switch

If the safety switch is triggered, then your generator won't start. You can check it by turning on the switch and then disconnecting both of its wires which should cause the engine to turn off immediately. If no change, replace it with a new one.

Faulty Fly Wheel Key

If the flywheel key is faulty, then your generator won't start. This part holds the pulley, which controls the timing of the ignition. If it is missing, you should replace it immediately with a new one for proper usage.

Bad Start Switch

If the start switch is bad, your generator won't start because you will not be able to put it into the "start" position. You can use a multimeter to check the switch and replace it if needed.

Bad Voltage Regulator

The voltage regulator is used to maintain a consistent power supply from the generator.

If it is faulty, you will not be able to keep your generator running because of low voltage levels, which can damage the internal components such as the brushes. Therefore, you should check this and make sure that it is not damaged and replace it if necessary.

Fuel Leak

If there is a fuel leak, you will not keep your generator running because too much fuel will go into the engine. Therefore, you should ensure that you don't have any leaks and replace them if necessary.

Manual workers repairing power generator

How do you reset an Onan 5500 generator?

If you have problems with your Onan 5500 generator, you should reset it. To do so, follow these simple steps:

  1. First, locate the primer button on the generator (typically on the side of the unit).
  2. Then, hold down the primer button for at least 30 seconds and release.
  3. Now, starter the generator and let it run for 15 minutes.
  4. By doing this, it should clear any codes that were on.
  5. If the codes do not clear, repeat these steps.
  6. In this case, if it doesn't reset the codes after several attempts, then contact your local Onan dealer.

How do you prime an Onan 5500 generator?

To prime your Onan 5500 generator, you will need to hold the prime button for 30 seconds. Typically, the fuel pump will stop ticking when the carburetor float-bowl is fuel. When this happens, you will be able to start your generator.

Why does my Onan 5500 generator keep shutting off?

Mobile moveable gensets portable diesel engine

There are various reasons why your Onan 5500 generator keeps shutting off. Let's take a look at them below:

Low Fuel Level

If your generator does not have enough fuel, it will automatically shut off to prevent damage. However, you should check the fuel level and add more if necessary.

Low Oil Level

Just like the case of a low fuel level, if your generator does not have enough oil, then it will automatically shut off. You should check the oil level and refill if necessary.

Clogged Fuel Filter

If your generator has a clogged fuel filter, it will shut off. You should clean the filter and replace it if necessary.

Check Circuit Breaker

If you are using your generator for your RV or Trailer, make sure that the circuit breaker is on or not tripped. If it is tripped, turn it on.

Worn Spark Plugs

If the spark plugs are worn out, your generator will shut off. So you should replace them if there is a sign of damage. Otherwise, you should have them checked just to be safe.

Overheating

In the case of overheating, your generator will shut off. You should let your generator cool down and then turn it back on to fix this.

Dirty Carburetor

If your generator's carburetor is dirty, it will cause your generator to shut off. Therefore, you should clean the carburetor and replace any worn-out parts.

Blown Fuse

If the fuse is blown, it will cause your generator to shut off. Therefore, you should replace the fuse and check the other circuit breakers to ensure they are on or not tripped.

Bad Ground Connection

If there is a bad ground connection, your generator will shut off. To fix this, you should check all of the components for a loose wire or screws and tighten them up with a screwdriver.

Final Thoughts

Like other mechanic machines, generators will have problems from time to time. If your Onan 5500 generator isn't starting, check the parts mentioned in this article. If you can't figure out the problem, then contact an Onan dealer for assistance.

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