Honda Lawn Mower Won’t Start – Beginners guide with pics
Honda makes reliable, well-designed, and constructed mowers. You bought one, so you already know this.
A gummed carburetor is the most common reason a Honda lawn mower won’t start. Other possible causes include:
I work on lots of Honda’s and major failures are very rare. Let’s begin by doing some basic checks. Sometimes this will solve the problem or at least point you in the right direction.
This guide will assume that components such as pull cord, throttle levers, etc. are working OK. If you think that this is not the case, I wrote a guide that covers all pull cord common problems – check out “Pull cord troubleshooting”.
Diagnosing a no-start Honda is pretty straightforward, carry out a few basic tests to eliminate ignition, fueling, and mechanical faults. Tests are not difficult, but you’ll need to execute them correctly to avoid burning time or replacing parts needlessly.
This post covers the subject pretty well, however, if you need video help, check out “Mower won’t start video”.
It covers the full diagnosing process and repairs of the most common causes of a no-start mower.
Check the Basics
If you need video help checking the basics, check out “Pre repair no start checks video”.
In the workshop, I find the majority of Honda mower engine problems are related to bad gas. Common symptoms of bad gas include, Honda won’t start, the engine starts then dies and engine surging.
Oil Level
Some Honda mowers won’t start if the oil level is low, this isn’t a flaw, it’s designed that way to protect the engine. It’s good practice to check the oil level every time you fill the gas tank. Check on level ground and with all wheels set to the same height.
The Honda will take.58 of a quart (.55lt) from empty. If you are in any doubt about how to check the oil, you’ll find this guide helpful – “How to check lawn mower oil”.
Check Oil – A Honda won’t like to be overfilled with oil either, this can damage the engine, cause it to smoke, leak oil and sometimes not start.
Gas Level
Is there gas in the mower? Sometimes the obvious is the solution, and as Sherlock Holmes says “we should check a fact is indeed a fact”. The customer may have filled the gas tank with what they thought was good gas.
At my shop, I have found many strange concoctions – diesel, water, white spirits, vinegar, and of course last year’s gas makes a regular appearance in the tank. The fix for bad gas – drain the tank and clean the carburetor. You might find this guide helpful, it walks you through the whole process – “Carburetor clean out”.
Gas Tap On
The fuel tap is used to cut the fuel supply to the carburetor. I tell my customers to turn off the fuel when the mower isn’t in use. It’s easy to forget to turn it on. Honda fit their fuel tap on the right-hand side of the engine when viewed from the front of the mower.
This short guide with pictures shows you where your gas tap is, what it’s for and when to use it. Check out “Where is my lawn mower gas tap”.
Air Filter
A blocked air filter will prevent the mower from starting. The Honda air filter needs to be kept clean, check it every 25 hours of use, and replace it every 100 hours. Honda fit tool-less air filter covers, which makes cleaning super easy.
The air filter cover is on the right-hand side of the engine, opposite the muffler. Cleaning the filter with compressed air would be nice, but banging on the ground will do just fine. This guide will help you service your mower in under an hour – “Mower tune-up”.
Plug Wire On
It’s easy for the plug wire to come loose, happens all the time. The plug wire lives right at the front of the engine, so it’s banging into shrubs and hedges and the like. It’s the black wire with the rubber boot on the end. Make sure it’s making good clean contact with the plug. Bad or no contact will give you a no start.
Choke On
I meet lots of customers who don’t know how to use the choke correctly, and I don’t blame them, it is likely they weren’t shown by the retailer. The choke is used to start a cold engine. A cold engine needs more fuel than a hot engine, so the choke creates a richer air-fuel ratio.
Some Honda’s will have the traditional choke lever and more modern mowers will have the auto choke set up.
Not sure if your choke is working? This guide will walk you through the testing procedure, see choke testing below.
If your mower doesn’t start on the 3rd attempt, it’s very likely the plug is saturated in fuel – a condition known as flooded. The fix is to remove and dry the plug or leave the mower for 30 minutes to dry out, then try again, this time without choke. Check out the Unflood mower video.
If you are in any doubt about how to start a mower, this guide covers it all, you’ll be a pro 2 minutes from now – “How to start a lawn mower”.
Choke On – Some Honda mowers are fitted with an auto choke and so the choke won’t be controlled by the lever.
Bail Lever On
The Bail lever or dead man’s lever is a safety feature. Its function is to stop the spinning blade within 3 seconds of release. It does this by shutting the engine off and applying a flywheel brake. If the bail lever isn’t held the mower won’t start.
This guide will walk you through testing for spark and how to change a coil, it’s simple. Only some Honda mowers will have the stop/start controlled by the bail lever. Other Honda’s have the stop/start control built into the throttle lever.
Check For Bad Gas
Bad gas is the number one cause of no starts. Your gas could be clean but stale, and mowers don’t like stale gas. Gas starts to go off after one month, it losses its ability to com-bust which causes poor performance and misfiring. When it goes completely stale, usually around 3 months old, it starts to solidify.
This has become such a big problem, last season I got a ton of questions about fuel carburetor cleaning.
Gas Stabilizer – It’s simple to use, just dump one ounce of gas stabilizer into 2.5 gallons of gas, fill your gas tank and run the engine to mix it throughout the fuel system, that’s it.
This stuff will protect and clean your fuel system and can be used in all gas-powered kit including 2 stroke engines. See video here.
Check out the “Carburetor cleaning tools” page, it lists all the tools I use including the gas stabilizer.
Gumming – It’s a carburetor killer, using a gas stabilizer will prevent a lot of problems.
That’s all the easy stuff checked, now we’ll dig a bit deeper. Bad gas has become a real problem, especially in Honda’s, the carburetors are so sensitive to contaminated gas and for that reason, we’ll perform the gas shot test next.
Try The Gas Shot
Your engine needs fuel, spark, and compression to start. Fuel, Spark, and Compression are broader areas than their title suggests. Testing will take into account the complete system, for example, fueling is more than just the gas, it includes carburetor, tank, air and fuel filters, gas line, intake manifold, etc.
The most likely cause of a no-start Honda is fueling, and so we will start there. The next most likely is spark and the least likely of all is a compression issue.
To quickly test for a gas issue – bypass the fuel system. We do this by pouring some fresh gas directly into the carburetor.
If you need video help, check out “Mower won’t start video” which shows you how to nail this test like a pro.
The symptoms of bad gas vary: mower won’t start; mower runs rough; runs but only with choke; splutters when cutting on a slope; dies when cutting grass; lawnmower starts and then dies.
Remove – Remove the air filter, by pressing the two plastic tabs.
Tilt your mower over and pour a cap full of gas into the carburetor.
Pull – Attempt to start the mower in the normal way.
There are two possible outcomes –
(1) Mower attempted to start or started – tells us we have a fueling fault. Check out the Choke system test below(2) Mower made no attempt to start – then we’ve likely eliminated a fueling fault, and the fault will probably be a lack of spark. Check out the Ignition system test below.
Does Your Honda Need A Tune-up?
Your Honda engine should be serviced at least once per season, ideally in the spring. Tune-up kit includes: oil; plug; air filter; fuel filter (if fitted); new blade (optional).Your Honda engine will likely be a GCV 160 or GCV 190cc.
The service kits will be identical, however, Items such as carburetors and blades will be different. Check out “Mower tune-up guide”.
Buying the tune-up kit online is easy. You can find your model code right at the base of the handlebars, on the body of the mower. Honda mower engines are very common and so you won’t have a problem getting a tune-up kit to match.
Test The Choke System
Your mower won’t start if the choke is faulty. In this next step, we need to be sure the choke system is working correctly. The correct starting procedure for a cold engine will require giving it extra gas to enrich the fuel/air mixture which a cold engine needs for a smooth start. Honda uses a choke plate type system to achieve a fuel-enriched condition. Your mower won’t start if the choke is faulty.
The manual version will have a throttle lever to control the choke. The auto choke version won’t have a choke lever. Instead, a wax thermostat mounted in the cylinder head heats and pushes on a lever that opens the choke plate.
To test we’ll need to remove the air filter, this allows us to view the choke plate. If you have a manual choke control, move the throttle lever to the full choke position to start a cold engine.
Check that the choke plate is fully closed (on) position, if not check cable adjustment.
Your Honda may have an auto choke. If so, when cold, the choke plate should be closed, as per the picture. If not, move the plate by hand to see if it’s stuck. If sticking, try WD40.
When the mower has started, the throttle should be moved to the run position. Check that the choke plate is in the fully open (off) position as per the picture. If not, adjust the cable.
A sticking choke will run poorly and puff black smoke from the muffler. Your Honda may have an auto choke. If so when hot, the choke plate should be open, as per the picture above. If not, replace the choke thermostat at the muffler.
If you found no issues with your choke system, move on to clean the gas bowl.
The Problem With Ethanol Gas
Honda recommends not using fuels with more than 10% ethanol. Ethanol is an alcohol fuel made from sugar, corn, and other plant materials. This alcohol is then blended with gas to make ethanol.
It’s claimed that the alcohol content of the ethanol will damage the carburetor’s rubber seals and hoses.
E15 contains 15% ethanol and is not OK to use in Honda mower engines. E15 burns hotter than other fuels, your mower is not designed to run at these temperatures. Ethanol absorbs moisture from the atmosphere.
If the fuel is left in the mower over the winter, the moisture collects in the carburetor. The water will often corrode and leave a varnish type deposit that blocks up the ports. This is what causes the poor running/no start.
If you need help prepping your Honda for hibernation, check out “How to winterize your mower video”.
How to Replace the Air Filter and Spark Plug on Your Honda Lawnmower
For many homeowners, summer is synonymous with lawn care, and that means ensuring that your Honda lawnmower is in good working condition. Old or worn air filters and spark plugs can result in overheating, power loss, erratic operation, and a failure to start properly. Fortunately, with a few easy steps you can have your Honda lawnmower back up and running like new.
The following is a step-by-step guide to finding and replacing the air filter and spark plug on your Honda Lawnmower.
It is important to use the correct air filter for your Honda lawnmower. Residential push-behind Honda lawnmowers come in a number of different models. To find the correct model of your Honda lawnmower, check the plate on the mower deck closest to the handle. The model number should begin with the letters HR. Use this sequence of letters to find the appropriate parts online at HondaLawnParts.com.
Air filters come in two basic types – foam and paper. Foam air filters can be cleaned while paper filters should be replaced every 200-300 hours of operation. Once you have determined the correct type of filter for your model of lawnmower, you can begin the process of replacing the old filter.
Filters
Clean filters are essential to a smooth running engine that is easy to start. Keep your equipment’s engine running clean with a replacement air filter, precleaner, fuel filter or oil filter. You’ll find the right filter for your Walk Behind Lawn Mower, Garden Tiller, Riding Lawn Mower, lawn edger or Snow Blower quickly so you can get back to your lawn and garden care. Use our Parts Diagram Tool to look up the filters for your Troy-Bilt or our Part Finder to make sure you’re getting the right filters for your machine
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You’re Probably Not Changing Your Lawn Mower’s Air Filter Often Enough
It’s critical that your lawn mower can breathe easily to run properly and last a long time. Therefore, you must either clean or change your lawn mower’s air filter often. How often? That depends on the size of your lawn mower and the size of its air filter, but it ranges from once a year to once a month.
Walk-behind mower engines under 10 horsepower usually have a 5-inch by 7-inch filter or paper air filter. You’ll want to swap this every 25 hours of mowing, but make certain its not clogged at least once a month.
Ironically, the tiny filter on many small mowers requires more maintenance than the larger filters on larger mowers. Because dust and grass can easily clog up one of these filters and starve your engine of air, I like to give them a quick visual inspection every time I mow. Luckily, you can often find these attached to the carburetor and view them by simply pulling off the engine shroud.
If your walk-behind mower has a small paper filter, you can remove it and try to knock the dirt off of it. According to the Power Outdoors website, you can check whether a cleaned air filter is safe to run by holding it up to the light and seeing if any light shines through.
Some walk behind mowers have an upgrade: a similarly-sized foam filter. While this filter may clog up just as often, you can wash it out with water and dish soap. Simply take it inside, wash it like a sponge. If it is not excessively dirty or torn, you can dry it and reinstall it. Note: after a foam filter has dried, you will want to rub a little filter oil onto it.
Rare walk-behind mowers have a paper filter filament wrapped in a foam pre-cleaner. You can wash this pre-cleaner like any foam filter, and maintaining it will help your paper filter last longer.
How often should you change a lawn tractor’s air filter?
Larger lawn tractors tend to have a circular paper air filter wrapped in a sponge pre-cleaner. Its a good idea to swap out this paper filter once a year or after 200 hours of mowing. But you’ll want to wash your pre-cleaner after 100 hours of mowing, or when it’s dirty.
Lawn mower engines in the 12-17 horsepower range often have a filter with both a paper and sponge element. This is so you can do many hours of mowing in one season without buying a new, large paper filter. But to maintain this filter, you will have to wash the pre-cleaner throughout the season.
How often do you have to wash this pre-cleaner? It depends on how much debris you’re mowing through. It’s a good idea to examine it weekly until you get an idea of how quickly it clogs. No matter what, you’ll want to replace this paper filter at the beginning or end of every season.
How often should you change your riding lawn mower’s air filter?
Large riding lawn mowers, with engines over 18 horsepower, often will have a canister or air intake box with a filter inside. You can probably get away with doing 250 hours of mowing before you need to replace your filter, but you will need to clean it at least every 100 hours.
Powerful, ride-on mowers often have an air filter set up much more like you’d find on a passenger car than what you’d find on a walk-behind mower. This increased capacity means you can operate the mower for 10 times as long as a walk-behind before replacing the air filter. That said, if the mower has a sponge pre-cleaner you must wash that whenever clogged to preserve your paper filter.
Remember, if your pre-cleaner is ripped or excessively dirty, then you must replace it. In addition, if your paper filter is so soiled you can’t see light when you hold it up to the sun, you must replace it as well.
Next, read our extensive lawn mower service schedule. Or, see for yourself how to change a lawn mower air filter in the video below:
How to Clean a Lawn Mower Air Filter
Kelly Burke is a professional turf manager who is accredited in organic land care and a licensed pesticide applicator.
Having a properly functioning air filter is a gas-powered lawn mower’s first line of defense against the dirt and debris that is kicked up during the mowing process. When the air filter is in good condition and working properly, it prevents dirt from entering the engine through the carburetor. But if the air filter is worn out, dirt and other debris can make their way into the engine, leading to potential start-up problems and a shorter engine life.
How Often to Clean a Lawn Mower Air Filter
Cleaning or replacing the air filter is simple lawn mower maintenance that will improve performance and extend the life of your mower. Clean the foam pre-cleaner every 25 operating hours. Replace the paper air filter once per season or after 300 hours of operation. In dusty conditions, more frequent cleaning and replacement may be necessary.
Tip
What You’ll Need
Materials
Replacing Different Types of Lawn Mower Air Filters
As well as foam, paper, and mixed filters, it’s also worth noting that some air filters are reusable while others are disposable.
What this essentially means is that you can clean some filters for reuse, while others must be replaced and cannot be cleaned. In fact, doing so may degrade their performance and put your mower at risk.
In general, paper air filters are disposable and foam lawn mower filters are reusable.
You can gently blow on and partially clean off a paper air filter mid-season, but I don’t recommend using compressed air on them – if it looks too dirty to function well, just buy a new one for under ten bucks.
It’s a small price to pay to keep your mower working well for years to come.
Why Air Filter Maintenance is Important
Your lawn mower won’t run (for long) without an air filter.
Engines need air but cannot deal with the debris and other items that may end up lodged inside if there’s no filter.
Air filters do all the dirty work to ensure your lawn mower runs seamlessly. However, occasionally you need to clean or replace the filter.
If enough debris gets into your engine, it’ll get clogged and won’t perform as it should.
That’s why regularly replacing the air filter is a wise move if you want to your mower to perform well for years to come.
When to Change the Air Filter on Your Mower
A common question is how often the air filter on a lawn mower needs to be changed. Most experts recommend that you check your mower’s owner manual for specific guidance that applies to your specific mower.
But you’re on the internet looking for the answer you need now.
My Recommendation
How often you need to change the filter on your mower can depend on a variety of factors, such as how often you use your lawn mower and in what conditions.
Needless to say, mowing three times a week in a dusty location is going to mean you need to change the air filter more frequently.
And when you’re mulching leaves in your yard there will be more dust kicked up and your filter will be working overtime.
Most homeowners can usually get away with changing their filters once a year. This means changing the filter around every 25 to 50 hours of use.
Whether you have a foam filter or a paper one, you can replace it with a new one by yourself, and it will take you 15 minutes (and probably much less) in your garage.
Replacing my paper air filter requires no tools and about 20 seconds of my time (including throwing the old one in the trash).
My best advice is to replace your filter annually, and visually inspect it before every mow.
Clean Your Lawn Mower Air Filter Regularly, Replace Annually
Time goes by quickly, so make sure to keep track of when you last changed your mower’s air filter.
As part of my spring mower maintenance I always install a brand new air filter in my mower.
But if you haven’t changed or cleaned your mower’s air filter, it’s a low-cost and easy fix to get your mower running like new again.
Hopefully this article has given you the information you need to keep on top of it going forward!