You were prepared for the next power outage by having a generator on hand. However, you were not prepared for it to stop running after you got it started.
A Honda generator may start and then die due to a plugged air filter, wrong choke setting, clogged fuel line, plugged fuel filter, dirty carburetor, bad gas cap, dirty spark plug, faulty ignition coil, low engine oil level, or old gasoline.
Follow all safety precautions listed in the Honda operator’s manual. This includes removing the spark plug wire and allowing the engine to cool before performing repairs.
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Follow all safety instructions provided in your equipment operator’s manual before diagnosing, repairing, or operating. Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.
11 Reasons a Honda Generator Starts Then Dies
Gas Tank is Empty
The first thing to check when your Honda generator quits running is the gas tank. I know this is an obvious thing to check, but sometimes it gets skipped when an owner is frustrated and trying to get the generator running again.
SOLUTION: If the tank is empty or low on fuel, fill it with fresh fuel.
Even if you have enough gas in your generator to make it run, you may have old gas that will cause it to run sluggishly and die. This is because old gas leaves behind varnish and sticky deposits that clog fuel components causing fuel restrictions.
Without sufficient gas, the engine won’t stay running. Because gas can begin to break down as quickly as 30 days after you purchase it, it’s important to purchase fresh gas and use it within 30 days.
This is easier said than done. You don’t always know when you are going to need the generator and how long you need to run it.
I recommend adding Sea Foam Motor Treatment to each tank of fuel to stabilize the gas and reduce moisture buildup so the fuel lasts a little longer before it breaks down.
Follow these tips to get the best fuel results:
- 4-cycle Honda generators require unleaded gasoline with a minimum 87 octane rating and a maximum ethanol content of 10%. Don’t use gasoline with higher ethanol contents.
- Use gas within 30 days.
- Don’t leave gas outdoors or in areas where it can attract moisture.
- Store gas in a dry place.
- Only buy enough gas you can use within 30 days. If you purchase more than this, add a fuel additive to stabilize the gas.
SOLUTION: Drain old gas into a container to be disposed of properly. Add fresh fuel with a fuel additive to stabilize and clean the fuel system.
Plugged Fuel Filter
You will find an inline fuel filter placed between the fuel lines to strain fuel before it enters the carburetor and engine. The filter’s purpose is to keep dirt and debris from wearing on the engine and causing damage.
Dirt trapped by the filter can build up keeping fuel from flowing through the filter when the filter isn’t regularly replaced. The engine may die because it isn’t getting sufficient fuel.
SOLUTION: Replace a dirty fuel filter.
Fuel Line Blockage
Another thing that can restrict fuel flow is a clogged fuel line. To find a clog in a fuel line, stop and start the fuel flow while checking the flow coming from each section of the fuel line.
Allowing fuel to flow into a container when evaluating fuel flow works best. Make sure the container is placed lower than the fuel tank because fuel can’t run uphill without the assistance of a pump.
SOLUTION: To remove a restriction from the line, shut off the fuel supply, remove the fuel line from the generator, and spray carburetor cleaner into the line to help loosen the clog. Next, blow air through the line using compressed air until the clog is removed.
Reinstall the line. If you can’t get the clog removed or you find your fuel lines are dry and cracked, you can easily replace it with a new fuel line purchased from your local hardware store.
The carburetor is often the reason a Honda generator starts and then dies. As mentioned before, old fuel can leave deposits. The deposits can plug the fuel jet and cause internal carburetor parts to stick.
When this happens, the carburetor is no longer able to get fuel to the engine so it will continue to run.
SOLUTION: Remove and disassemble the Honda carburetor. I find taking photos along the way helps when reassembling it.
Clean it to remove gummy deposits and crusty buildups that remain from running old fuel and fuels with ethanol. If your carburetor is excessively dirty or has broken components, you may have to rebuild or replace it.
Clogged Air Filter
The air filter is used to keep dirt from getting into the engine through the air intake. Always run the generator with an air filter to minimize damage to the engine.
Not only should you always use a filter, but you should always make sure it is clean so it doesn’t restrict the amount of air that passes through the filter. An air restriction will cause a Honda generator to stop running.
If you use a generator like the average homeowner, I recommend replacing the air filter once a year. You must also check the filter’s condition before each use and clean it or replace it as necessary.
For the average homeowner, I recommend replacing the air filter annually and cleaning it a few times a year. When you notice the filter is extremely dirty or damaged, you must replace it.
SOLUTION: If you find your Honda air filter is clogged with dirt, clean it using the procedure below. Consult the Honda operator’s manual if you are using a different type of filter or are unsure of the type of filter installed on your generator.
Clean a Honda generator foam-style air filter
- Remove the air filter from the housing.
- Wipe out any dirt remaining in the air filter housing and cover. Don’t allow dirt to fall into the air intake.
- Inspect the foam filter for damage and replace it if needed.
- If the filter is in good condition, clean it in soapy water and rinse it until the water runs clear.
- Squeeze the filter and allow it to dry.
- Saturate the filter in clean engine oil so it is fully covered. Then squeeze the filter to remove excess engine oil. You don’t want it dripping with oil.
- Install the air filter.
- Reattach the air filter cover.
Wrong Choke Setting
A Honda generator with a cold engine must be started with the choke closed to restrict air. Once the engine warms up the choke must be adjusted to the open position to allow more airflow so the engine continues to run.
SOLUTION: If your engine starts and then shuts down right away, you need to make sure the choke is off and in the open position. Also, check to make sure the choke plate is not stuck and is opening and closing correctly.
Bad Gas Cap / Fuel Tank Vent
The fuel tank needs to vent so it doesn’t form a vacuum. The fuel tank vent on a Honda generator is usually built into the fuel cap.
When the fuel tank cap is plugged or damaged, the air is no longer able to pass through the cap. The vacuum that forms in the tank will prevent fuel from getting to the carburetor so the Honda generator will no longer run.
You can determine whether the fuel tank vent is your problem when the generator won’t start until you loosen the fuel cap to allow air into the fuel tank. If the generator starts and runs with the loosened cap, try to replicate the issue by retightening the fuel cap.
Allow the generator to continue to run to see if it begins to run sluggishly and shuts down. You most likely have a problem with the fuel tank vent if it does shut down and won’t restart until the air is allowed into the tank.
SOLUTION: Replace the gas cap when you find the fuel tank is no longer venting properly.
Dirty Spark Plug
You must have spark to start and run a Honda generator. So, if the generator started, you did get enough spark for it to run. However, the spark plug may be very dirty or damaged causing intermittent spark causing it to die.
SOLUTION: Remove the spark plug and check its condition. If the tip is very dark in color, the electrode is worn or the porcelain is broken, you must replace the spark plug with a new one.
If it appears in good condition, clean it with a wire brush and check the electrode gap and securely attach the spark plug wire. A loose wire or incorrect spark plug gap can also cause the generator to quit running.
Bad Ignition Coil
Before checking for a bad ignition coil, make sure your spark plug is in good condition. The ignition coil provides voltage to the spark plug so it can start the engine.
If the spark plug isn’t able to fire due to a bad spark plug or ignition coil, the engine will not start.
SOLUTION: Check the continuity of the ignition coil using an ohm meter. If you find a break in the continuity, replace the ignition coil.
Insufficient Engine Oil Level
Your generator may be running for a while and then suddenly stop. Check to see if the low engine oil light is on. When the oil level is low, most Honda generators have a sensor that will shut it down to protect the engine from damage. It will not restart until the engine oil level is corrected.
It may be frustrating that it won’t keep running. However, the generator shutting down is a good thing in this case.
Continuing to run an engine that is low on oil can result in significant engine damage because a lack of sufficient lubrication will cause friction to build in the engine. The engine can become so hot that the parts can begin to melt.
SOLUTION: To check the engine oil level, begin by placing the generator on a flat-level surface. Remove the oil fill cap and wipe off the dipstick with a clean cloth to remove the oil.
Reinsert the dipstick into the oil-fill tube, but don’t screw on the cap. Remove it and look at the oil level on the dipstick. Ensure it is in the full range on the dipstick.
If it is not, correct the engine oil level by removing or adding a little oil until it is at the correct level. When you find you have the correct engine oil level and the low oil sensor stays on, you may have a faulty sensor. It’s best to take the Honda generator to a service center to be repaired.