How to Change Spark Plugs on a Lawn Mower
Spark plugs may be a small part of your lawn mower, but they are rather important. If a spark plug is old or not working properly, your mower’s engine can have difficulties starting or running. It is always good to check your spark plugs if you begin experiencing any of these issues.
For lawn mower spark plugs, the maximum lifetime from manufacturers is two years. While this is the maximum lifetime, it is not the ideal lifetime. For your engine to remain at optimum performance, it is recommended to replace your spark plugs once a year or after 30 engine hours. Since your lawn mower needs regular, annual maintenance, it is easiest to include replacing spark plugs as part of your maintenance routine.
What are the required tools for changing my mower’s spark plugs?
Changing your lawn mower’s spark plugs doesn’t take a lot of tools. The job can be done with a regular socket or a wrench and spark plug socket. Along with this, you will also need a spark plug gap gauge. The spark plug gap gauge is a tool to help you ensure the spark plug is installed to the exact measurements that the manufacturer recommends.
Replacing the spark plug in your lawn mower can be accomplished in six simple steps.
Honda 98079-56846. Alternative spark plugs
There are 105 replacement spark plugs for Honda 98079-56846. The cross references are for general reference only, please check for correct specifications and measurements for your application.
Replacement spark plugs for Honda 98079-56846 on Ebay
Advanced search
Choose brandname and start typing model number.
The spark plug Cross References are for general reference only. Check for correct application and spec/measurements. Any use of this cross reference is done at the installers risk.
Copyright © 2013-2023 sparkplug-crossreference.com All Rights Reserved. As an Amazon Associate we earn from qualifying purchases. As an eBay affiliate, we earn a commission from purchases made through this site. Web Site functionality, contact info@sparkplug-crossreference.com Read our privacy policy.- Do Not Sell My Personal Information
Honda GCV170 Engine. Specifications
The heart of the Honda HRN Series is the all-new easy starting four-stroke Honda GCV170 engine, delivering nine percent more power and 18 percent more torque than the Honda GCV160 engine in the outgoing Honda HRR Series of lawn mowers. power and torque relate directly to the ability of the machine to tackle tough mowing conditions while still producing the clean, even cut prized by people who are passionate about their lawns. torque means more force is being delivered to the blades, which results in easier and faster cutting – especially in heavy, thick grass where stalling can occur. The power and torque of the new Honda GCV170 engine provide more stable RPMs for greater consistency in cutting, mulching and bagging. Increased displacement in the new GCV170 engine also contributes to more power and torque as compared to the GCV160 engine in the HRR Series.
Air-cooled 4-stroke single cylinder gasoline engine (OHV)
Maximum Power Output (kW[PS]/rpm)
Maximum Torque (N▪m[kgf▪m]/rpm)
Length x Width x Height (inches)
Engine Oil Reserve Capacity (L)
Fuel Consumption (L/hour) at continuous rated output at 3,600 rpm
The SAE J1349 standard measures net horsepower with the manufacturer’s production muffler and air cleaner in place. Net horsepower more closely correlates with the power the operator will experience when using a Honda engine powered product. The power rating of the engines indicated in this document measures the net power output at 3600 rpm (7000 rpm for model GXH50, GXV50, GX25 and GX35) and net torque at 2500 rpm, as tested on a production engine. Mass production engines may vary from this value. Actual power output for the engine installed in the final machine will vary depending on numerous factors, including the operation speed of the engine in application, environmental conditions, maintenance and other variables.
Total height varies depending on model type; the height indicated here is based on the N3 type crankshaft.
Honda HRU19D Lawnmower Full Service (Carburettor, Oil, Spark Plugs, Blades)
The closest manual I could find is the one for the HRU19K1. While there are lots of good videos on this (such as eReplacementParts.com, Steve’s Small Engine Saloon and Bruce Pender), for those of us that prefer to read, here are step by step instructions.
In the past year, this mower has become hard to start. Needs a carby clean and while I’m at it, might as well service everything.
Carburettor and Air Filter
Step 1 Air filter
Shut off the fuel valve on the hose that runs into the carby. Take off the air filter cover and the 2x 10mm bolts that go into the engine. Examine air filter and replace if bad.
Step 2 Fuel Hose
Undo the hose underneath (fuel line). You need to pull the retaining clip out of the way with pliers and then slide off the hose.
Step 3 Linkages
Tilt the carby and undo the 3 linkages.
Step 4 Remove carby
It should come out now. It’s pretty dirty.
At this point I should have removed the front and read gaskets but I did this in the middle of Step 6.
Step 5 Float Bowl
Turn it upside down and undo the 10mm nut. Remove the bowl.
Step 6 Float
Remove the float pin and then the float.
It is at this point I removed the front and rear gaskets.
Don’t lose the float valve that attaches to the float.
Step 7 Main Jet
Using a flat blade screwdriver, unscrew the main jet and tap the size of the carby until it comes out.
Step 8 Main Nozzle
After some more tapping the main nozzle should come out.
Step 9 Clean
Everything looked relatively clean. I didn’t want to mess with the idle screw and clean the pilot jet because it affects idle and not my starting problem (see for how to do this eReplacementParts.com).
Clean everything with carburettor cleaner, paying particular attention to the air flow and fuel flow paths indicated in the figure below.
Step 10 Put Back Together
Oil Change
Step 1 Check Oil
Remove the dip stick, check the oil level and look at the colour of the oil. Mine had not been used much the previous summer and looked good so I’ll change it next year.
Step 2 Change oil
If you need to change the oil, do so when it is warm. Close the fuel valve and tip the oil out at the dipstick opening. Use SAE 10W-30 4 stroke oil.
Spark Plugs
Step 1 Remove Cable
Step 2 Remove Plug
Step 3 Check Plug
Gap is supposed to be 0.7-0.8 mm so let’s go with 0.75 mm.
Step 4 Put Back Together
Blade replacement
Step 1 Remove Cable
Remove spark plug cable (so engine can’t start on you).
Step 2 Turn on Side and Remove Blade Disc
Turn off the fuel valve and turn on its side with the air filter facing up. Use a block of wood to wedge the blade so it won’t turn. Using a 14 mm socket, undo the nut for the blade disc.
Step 3 Examine blade
The part number for 4x the normal height blades is 06720-VK0-600. It took me a while to find this handy table.
I purchased new blades from Online Mower Spares who I highly recommend.
Step 4 Remove blade nuts
Step 5 Clean
I used a wire brush to clean the blade disc.
Step 6 Attach New Blades
One thing that I didn’t know is that the blades are not perpendicular to the disc. They are at a slightly acute angle. If you make them perpendicular, they hit the side of the mower (only found out after I put everything back together). I used the shadow of the old blade for alignment.
Make sure you tighten the self-lock nuts for the blades according to the manual (29.4-39.2 Nm) using a torque wrench!
Step 7 Put Back Together
Put the blade disc holder back on the mower. Check torque with torque wrench, it should be 49.0. 58.8. Nm Replace the spark plug cable and open the fuel valve.
What do the lawn care pros say about replacing a spark plug on lawn care equipment?
Across the board, the resounding response from lawn care providers was that they changed their spark plugs annually. With 64% reporting to us that they only changed their spark plugs once a year.
This number suggests that spark plugs last MUCH longer than 25 hours.
Think about it we are talking about lawn care professionals. So if they run their mower for a minimum of 20 hours a week for 39 weeks of the year for example. That means spark plugs easily last over 780 hours before needing to be replaced.
What did the rest of the lawn care professionals say about changing their spark plugs?
Well, the second most popular response we received was 30% of lawn care pros stating they NEVER change their spark plugs.
Finally, 3% of lawn care providers said they changed their spark plugs after the ‘recommended’ 25-30 hours of use, and another 3% reported to us that they swap spark plugs out on a monthly basis.
Remove Spark Plugs Regularly to Prevent Seizing
Look, whether your spark plug ignites the fuel or not is one thing. But one huge issue that can occur when your spark plugs are not maintained is seizing.
Here’s the deal, a bad spark plug isn’t a huge problem, but a seized spark plug can be a major headache. And could potentially cause other problems down the road.
Spark plugs can seize inside the engine block if they are left in too long, or improperly installed.
So, even if your spark plugs are still good, you want to be sure to remove them annually and add an anti-seize agent at the very least.
Spark Plug Maintenance at the End of the Day
Simply put, if you are a homeowner you probably can’t go wrong changing out your lawnmowers spark plugs annually.
Most homeowners use their lawnmowers well over 30 hours annually. So it simply makes sense to swap out your spark plugs on an annual basis.
On the other hand, if you are a lawn care pro, only changing your spark plugs once a year may not be enough. And you do risk sacrificing your lawnmower’s performance by not changing your spark plugs frequently enough.
While it’s a fair assumption that changing out your spark plugs weekly is a bit overkill. You may want to consider changing your spark plugs on a monthly basis if you are a lawn care vendor.
But the reality is, your mowers spark plug goes mad, it’s not a difficult fix. At least if you happen to carry spares on hand.
Want more to read? Check out this article on how to winterize your lawn care equipment.
Hi, I’m Gene Caballero and I’m the co-founder of GreenPal. At GreenPal, we’re helping hundreds of thousands of Americans solve one of the trickiest problems: a reliable, fast, and affordable way to get lawncare taken care of. On behalf of GreenPal, I’ve been featured in the Indianapolis Star. the Sacramento Bee. Entrepreneur. Inc.com. and dozens more. Please feel free to say hi on or connect with me on LinkedIn.
LAWN MOWER SPARK PLUGS
Tired of re-cranking your lawn mower every time it bogs down? It’s probably time to change the plug rather than putting it off until the next time you mow your lawn. In fact, your lawn and garden equipment can be a major source of air pollution and hard on the wallet. Approximately 54 million Americans cut their grass every week. In the process, about 800 million gallons of gasoline are burned each year. The California Air Resources Board estimates that a lawn mower can emit about the same amount of pollutants in 1 hour as driving your car for 13 hours.
Extensive testing has shown that E3 lawn mower spark plugs will burn fuel more completely in your lawn mower’s engine before the exhaust event ever occurs. And. E3 lawn mower plugs are engineered to last longer, significantly reducing the number of discarded plugs that wind up in local landfills. So, don’t delay. Stop by your favorite auto parts, home improvement or hardware store to pick up an E3 for your lawn mower. By replacing the plug and cleaning the air filter, you can eliminate many of those frustrating “stop-and-go’s” for repeatedly cranking your stalled engine.
Ever notice that Cloud of blue smoke that fills the air when you crank your edger, blower or weed eater? The Environmental Protection Agency (EPA) estimates that older engines like those used for landscaping equipment pose significant environmental concerns. In fact, recent environmental studies suggest that in small engines, up to 30% of the exhausted gases is raw fuel. That’s bad for our planet and wasteful of your hard-earned dollars. Help to make a difference. Replace your standard plug with an E3 small engine spark plug for a cleaner, more complete burn.
E3 small engine lawn mover spark plugs have the same patented Edge-to-Edge DiamondFIRE ground electrode that has been proven to burn fuel more efficiently inside the motor’s combustion zone well before the exhaust cycle occurs. It has been suggested that the best way to fight global warming is to “Think Globally and Act Locally.” This is an ideal opportunity for you to help reduce the amount of carbon monoxide, carbon dioxide and other harmful hydrocarbons that are exhausted into the air we breathe. Visit our website’s Where to Buy section to locate the E3 retailer nearest you.