Lawn Mower Oil Change Questions

[Dan in Pasadena]

Do you guys change your lawn mower oil each year? Yeah, I'm guessing a few will say they've never changed the oil in their mower!

I have a homeowner grade Honda mower that's maybe 7-8 years old (guessing). I change the oil each year before start of summer. I admit I never check the level but should. Now I'm noticing it smokes a bit on start up - but not always! What gives? Does my Honda have overhead valves with valve seals that have gotten hard?

 

[Zeke]

Hey, Dan. Why do you wait until the start of the season to change? Wouldn't it be better to change at the end and run it one mow?

Honest question.

 

[npp]

Do you guys change your lawn mower oil each year? Yeah, I'm guessing a few will say they've never changed the oil in their mower!

I have a homeowner grade Honda mower that's maybe 7-8 years old (guessing). I change the oil each year before start of summer. I admit I never check the level but should. Now I'm noticing it smokes a bit on start up - but not always! What gives? Does my Honda have overhead valves with valve seals that have gotten hard?

Should change the oil at the end of the season so it doesn’t sit all winter with moisture and acid in old oil and it will be ready to go with fresh clean oil in the spring. My Honda is overhead cam, not sure about valve seals. Hey it’s a Honda, all I do is change oil and add gas, still on original spark plug.

 

[Dan in Pasadena]

Never thought about it to be honest. Either way the oil will sit mostly unused over the winter. If now/soon @ end of growing season I suppose it takes contaminants with it as it leaves!

 

[ChefRex]

In the end of season camp.

 

[vwpieces]

I got a $30 used cheapo MTD mulcher mower. Changed the oil once in 5yrs because it started sounding bad while running (knocking kinda). And that oil I put in was "used" from another automotive engine I built and only ran as break-in oil for 20min.
4yrs later it's still going strong, no odd sounds since and doesn't smoke. I expected the deck to rust by now and have a spare engine from a freebie with rotted deck. I do check oil level occasionally but it's had lack of use this year because of the heat wave.

The way I see it, my mower will never see fresh clean New oil. And the engine will probably outlast the deck.

But if I lived where gas engine lawn equipment was getting banned I might be more inclined to take better care of it.

 

[Dan in Pasadena]

^^^ I guess I don't understand WHY you wouldn't change the oil in an engine just like you would (I assume) in an automobile? Why abuse the engine like that?

Unless of course you never change oil in cars like my (idiot) brother-in-law who claims you only need to change filters. I don't even bother to tell the know-it-all that there is much more to be concerned about with oil than particulate contamination.

 

[clutchee]

Change oil and filter in mine every May. Once a year.
For amount paid for it, need it to last!

 

[BlakeTheCarGuy]

Change the oil in mine beginning of each year. Probably will do it towards the middle or so from now on though cause we got behind this year. Change it at the beginning so it’s fresh and not sitting around. I change it in both riding mowers and the push mower at the same time.

 

[CJM8515]

i have a toro that doesnt have a drain plug, a friend sold it to me for 100 bucks and it was pretty new at the time (they bought a rider). 3 seasons i checked the oil and it is a bit low but still in the normal range. should it blow ill just nab a mower someone screwed up and throws out on bulk pick up day. ive gotten my parents 3 free mowers over the years that way. typically just need something little fixed.

 

[vwpieces]

^^^ I guess I don't understand WHY you wouldn't change the oil in an engine just like you would (I assume) in an automobile? Why abuse the engine like that?

Unless of course you never change oil in cars like my (idiot) brother-in-law who claims you only need to change filters. I don't even bother to tell the know-it-all that there is much more to be concerned about with oil than particulate contamination.

Don't assume...
I have built every engine in every vehicle I have owned for 30+ years. And many engines built for others under my belt.
4yrs on my "used" oil I changed in the mower is still somewhat translucent.
Why spend money needlessly? Only paid $30 for it and buying new oil every year would have cost as much as the mower.
I also have a free spare engine that I doubt I will ever need. While I would not use the "used" oil on any other vehicle that sees the road there is nothing wrong with it getting used in a mower. It has 20min runtime on it and a very high zinc content. Why throw it out? But again, why waste it on annual oil changes in a mower that sees 10hours a year.

Yeah, 10 HOURS/YEAR. I have not seen runtime mentioned in this thread. So value the opinions for what they are.
I have a few cars that are driven infrequently, one has only been started 4X in a year and has not been driven on a road in that year. Am I supposed to change the oil every year regardless? No thanks... Cars get run long enough to burn off moisture, shut off. I will still change that oil according to mileage. Shoot, If and when I need to use my snow blower, it sees more than 10hrs in one use, one snow fall. Got more asphalt than grass.

When I need a new mower I will buy another... the cheapest one, if not free, that I can find. Fixing one that doesn't run and usually done for NO Money. Engines usually are not the reason a mower gets discarded. Bad gas or Owner induced "repair", oiled up air cleaner from tipping it to the wrong side, blades installed upside down etc...
Buy a New mower... I will gladly take the old one off your hands

I have never replaced a spark plug in any of my lawn equipment either. Have a 1995 2-stroke Stihl string trimmer with original plug in it. Guess I am neglecting that too.

 

[rharman]

Hey Dan. I have a Honda as well. Electric start - bought it in 2011 after screwing up my rotator cuff. My wife wanted the electric start and, I have to say, I'm now a believer.

Change the oil every year in the mower and Sears (Briggs & Stratton) edger, usually around November - no reason, that's just how it's worked out. I do check the level a couple of times a year. Most recent plugs & air filters change was Nov. 2020.

Since we have no seasons in SoCal, I don't worry about begin/end of season. In summer, we have to mow weekly, in winter it will be every 2-3 weeks. But, we mow year 'round.

It's cheap insurance...

 

[mikegt4]

I change the oil and filter at the end of every mowing season, must be working as this is the 21st. year for my Walker zero-turn. I also pull the tin off the engine and clean the grass out of the cooling fins, overheating can kill an engine in short order.

 

[Firebrick43]

Change it every 50 hours, or about 2 times a year. The 18hp kawasaki on the exmark is 18 years old now. Still starts on the first pull.

 

[Ak Jim]

Change mine in the fall just before it snows, l like to it to have clean oil for storage. It takes about 2 hours to mow the yard. Some years I change it 1/2 way thru the season.
As a side note WTF is up with the new mowers with out a drain plug? How are you supposed to change to oil?
One final not the mower I mentioned above is 26 years old.

 

[vwpieces]

As a side note WTF is up with the new mowers with out a drain plug? How are you supposed to change to oil?

No Oil Changes​

Just check and add as needed​

Engine maintenance made easy with no oil changes needed ever*. Simply check your oil levels, and add as you go.

Just Check & Add™ No Oil Change Tech | Briggs & Stratton

Goodbye messy oil changes, hello easy. With Briggs & Stratton Just Check & Add™ technology, you never have to change your push mower's oil again.

www.briggsandstratton.com

Even I would still change the oil more often than they tell ya to.
2 cars I have built engines for have extended run synthetic oil in them. But I would never go the claimed 10K interval.

 

[Ak Jim]

No Oil Changes​

Just check and add as needed​

Engine maintenance made easy with no oil changes needed ever*. Simply check your oil levels, and add as you go.

Just Check & Add™ No Oil Change Tech | Briggs & Stratton

Goodbye messy oil changes, hello easy. With Briggs & Stratton Just Check & Add™ technology, you never have to change your push mower's oil again.

www.briggsandstratton.com

Sorry but that’s just snake oil. Sure never need to change the oil and throw the mower away after 4 or 5 years. Especially on an engine with out an oil filter. They’re just guaranteeing you’ll be back sooner to buy another one.

 

[vwpieces]

Sorry but that’s just snake oil. Sure never need to change the oil and throw the mower away after 4 or 5 years. Especially on an engine with out an oil filter. They’re just guaranteeing you’ll be back sooner to buy another one.

Obviously true.
But if that engine burns enough oil to be topped off enough that the oil is still usable, it is polluting more than it should be allowed.
But on that same note: blocking off carb adjustment screws does the same thing. Eventually renders it useless to a point it will not run. Most people will ad more choke to keep it running, if it has a choke... and doing so makes it pollute even more.

Some small mower engines have the drain plug under side of the deck, burred in the caked grass. Has a square inset and pipe threaded. Not easy to get out or even find. Just tip it over and dump the oil out the same place you ad more to it.

 

[Jeff C]

Pure speculation but I’m willing to bet a good portion of the general population never changes the oil in their lawn mower.

 

[James-W]

I normally change the oil and the filter in my rider mower at the end of the mowing season. Last year i didn't do it because I had purchased the new mower last Spring and we didn't have very much rain so I only put a few hours on it. I don't have a push mower, I use a weed wacker to do the areas where I can't get with the rider mower. Changing the oil and the filter is much less expensive that having to buy a new rider mower.

 

[James-W]

Sorry but that’s just snake oil. Sure never need to change the oil and throw the mower away after 4 or 5 years. Especially on an engine with out an oil filter. They’re just guaranteeing you’ll be back sooner to buy another one.

I don't recall ever seeing a push mower with an oil filter on it. Not saying there aren't any, just saying that I have not seen one. As far as I know, usually oil filters are used on larger lawn mower engines and not the small engines.

 

[Ak Jim]

I don't recall ever seeing a push mower with an oil filter on it. Not saying there aren't any, just saying that I have not seen one. As far as I know, usually oil filters are used on larger lawn mower engines and not the small engines.

Exactly. Push mowers don’t have a filter which at least in my opinion makes their claim that you never have to change to oil seem even more outrageous.

 

[vwpieces]

Exactly. Push mowers don’t have a filter which at least in my opinion makes their claim that you never have to change to oil seem even more outrageous.

Buddy trash picked a JD I thought had a filter... quick search I found this JX75 model that has one. But I do not think his was the same.

 

[Jeff C]

Buddy trash picked a JD I thought had a filter... quick search I found this JX75 model that has one. But I do not think his was the same.

Those things are beasts. I have an old Deere 14SB which is the same mower best I can tell except silver color. I remember going with my dad when I was 10 years old (30 years ago) to buy it. Ours didn’t have an oil filter but I know it was an option. I still have the thing and use it for those tight spots the riding mower won’t fit. I had to do some repairs to the drive wheels a few years ago and was impressed with the parts that were still available from John Deere.

 

[4x4Pete]

Do you guys change your lawn mower oil each year? Yeah, I'm guessing a few will say they've never changed the oil in their mower!

I have a homeowner grade Honda mower that's maybe 7-8 years old (guessing). I change the oil each year before start of summer. I admit I never check the level but should. Now I'm noticing it smokes a bit on start up - but not always! What gives? Does my Honda have overhead valves with valve seals that have gotten hard?

I think the valve guides themselves are wearing on your mower. Sometimes there's a puddle of oil there and a bit gets drawn down the intake valve and gets burned on startup. No big deal. I had a really old Honda generator, by old I mean thousands and thousands of hours on it. It didn't have valve seals but the head was oriented up rather than on its side. It smoked on startup as well as it should have with the hours on it.

When and if you change the oil is entirely up to you. It's yours do with it what you want.

 

[bwringer]

Pure speculation but I’m willing to bet a good portion of the general population never changes the oil in their lawn mower.

Agreed. I strongly suspect the manufacturers noticed that 99.999% of mower owners have never ever even once considered the slightest possibility of even thinking about anything resembling the oil in the engine, and just... went with it.

And then some evil genius had the bright idea of turning "never change the oil", which is what absolutely everyone was doing anyway, into some sort of breathless marketing ****, and, well, here we are. And if you think there was some sort of testing, or engineering or design change, other than removing drain plugs to save that crucial ha'penny... LO frickin' L.

Anyhoo, yeah, I change mine in the fall, whether it's actually needed or not. No drain plug on my mower's Honda engine (these have been missing drain plugs for aeons), so the approved procedure is to flip the mower on its side and drain the oil out the filler. It's a high-stakes balancing act that takes some careful management and coordination, and a mostly empty gas tank, but it can be done.



Around about April or May, depending on your latitude, sneak a peek into the back room of any retailer selling lawn mowers. You'll see dozens of shiny mowers with a light coating of grass back there because people bought them, ignored the many brightly colored stickers and warnings discussing the oil, threw away the attached bottle containing some mysterious, meaningless substance, dumped in gas, and yanked the string. The distance they got before the engine seized is variable. And then it's back to the store with the "defective" mower, to scream and pout and stamp their little ignorant feet.

Same goes for gadgets with 2-cycle engines. Quite a few get ruined fresh out of the box with straight gas. Many get ruined by various combinations of ancient random gas mixed with random quantities of random oils.

A depressingly large number of people are medically incapable of understanding lubrication.

 

[laser3kw]

No Oil Changes​

Just check and add as needed​

nope! can't bring myself to do that. I have an "oil Extractor" and **** it out through the fill port. Also, some of those have diagrams on how to change the oil of those models. You open the fill port and turn the mower over and pour it out through the fill port. Hmm? I guess that is easier...

 

[dougf]

I've never changed the oil in my push mower. I check it once every three years. It's just a beater.
My riding mower I change annually and check weekly.
My LS MT125 I check daily and change every 100 hours.

I guess for me it depends on how expensive the equipment is!

 

[zmotorsports]

I'm pretty **** about changing the oil in my OPE. It gets changed out at the end of each season so it doesn't sit in the off-season with contaminated and acidic oil in the crankcase. I also clean the decks and sharpen the blades on the mowers and spray with some WD-40 to prevent corrosion in the off-season. For the snowblower, I service the engine and lube the cables is about all. My 21" Snapper walk-behind mower was purchased new in 1991 and is still going strong on original engine with this practice. I know many say not to waste money by changing the oil but I mow twice weekly and just can't bring myself to abuse a piece of equipment by not servicing.

As for your blowing smoke issue, what color is the smoke? If it is black it could be something as simple as a dirty air filter causing a rich condition at startup but if it is blue, it could be valve guide seals. Many small engine manufacturers don't run valve guide seals on the exhaust valve, only the intake but they are quite easy to replace. I have had to replace my valve guide seals twice in 31 years now when it starts to expel a hint of blue smoke on startup after a shut-down.

 

[nh_yota]

In the 10+ years I've had my mower I've changed the oil twice, I think.

It doesn't get a lot of use because I have a tiny yard so it just seems like a waste to dump out perfectly good oil.

 

[Wrench97]

I have one of the B&S no change required motors, I **** it out in the spring sharpen the blade and hand it over to Jr to handle the rest.
When he moves out I told him to take it with him I'll hire a lawn service.............................

 

[engineer2]

25 year old Craftsman mower with a Honda engine.
I change it every other year. This spring it was still clean and full, so I'll do it at the end of the season.

My snow blower with the Predator engine says every 25 hours of use.

 

[Pen & Wrench]

A small engine has about 3 things going for it, an air filter, air cooling and oil. When we had a part time lawn mowing business I changed oil every 20 hours on the walk behind mower, which was about once a week. That same mower now only mows the back yard, about 10 minutes per mowing, we just change it once a year. The diesel Kubota engine in my Grasshopper front deck mower can go 100 hours, and I change the oil and filter every 50 hours. It has 866 hours on it (not all that much for a diesel) and still runs like it was new. Keeping clean oil and especially a clean air filter can add a lot of years of life to a small engine.

 

[65ranchero]

I change the rider oil and filter at the end of the mowing season drop the deck and scrape it down, sharpen the 3 blades spray down the bottom of the deck with Fluid Film.
Maybe a full tank of ethanol free with red Stabil. and put it on a trickle charger
Kiss it good by and say see ya in the spring,

 

[bobg03]

I don't mow anymore, but when I did in another life I had a Cub Cadet that i changed every other year, I also had a push mower to get where the tractor couldn't mostly along my stone walls. I would buy a halfway decent pushmower on sale and just run it, first Briggs and Stratton went 12 years before if fell apart, second one was on year 13 and still running when I sold the property. The only thing I ever did was run em out of fuel before winter and sharpen the blades when needed. Can't recall ever checking the oil, probably ran about 1 and 1/2 hours tops once a week.

 

[imagineer]

I change the oil at the start of the mowing season, and check the oil level at each fuel fill-up (usually every other mowing). I do all the greasing and other maintenance then too.

For reference, this 'was' on a Snapper 52" walk-behind with a 16hp B&S Vangard V-twin, that I bought (used w/ 900 hours on it) in '99 and mowed with it until this past October when it spectacularly self destructed (at an estimated 2600 hours).

 

[Dan in Pasadena]

Yes, I suppose all of us can do whatever the hell we want with our own mowers but vwpieces "logic" about saving money by not changing oil is just ludicrous to me. The very few dollars spent once per year - an amount so low we all piss it away almost daily without even realizing it - to save many hundreds (if not a thousand by the time it's truly worn out) for a new mower strikes me as just dumb.

You do things your way, I'll do mine...as ever I suppose. Good to know it has no valve seals. I'll try changing oil as soon as this summer heat lets up as I use it pretty sparingly in Fall and Winter. Usually every other week to clean up leaves more than actually cut turf.

 

[K13]

I had a mower I ran for 20 years never changed the oil once. Ran fine, didn't smoke. Only reason I got rid of it was the neighbor decided he wanted to go electric and gave me his brand new gas mower he had bought two years earlier. I would guess 99% of mowers out there never have their oil changed. I leave the gas in the tank over the winter, no stabilizer, as well which can be 7-8 months of no use here and my mower starts up first pull every year.

 

[stick70]

Dan, I was a Honda small engine test engineer for many years. Admittedly I didn't read this whole thread so forgive me for any duplicate service information, but here you go. I'm going to assume you have a GC series engine, either 160/190, or 170/200.

Our service manual recommends changing the engine oil at the beginning of the season or every 50 hours run time. There is also a change after the first 5 hours of use, but you'll be well past that. I've always used an oil extractor, standard 5-30 is fine. The no tool way is to just dump it on it's side and pour it out the spout. I can tell you though, this engine will pass a very abusive high hour durability test with no oil changes, only topping up. Changing will of course keep the engine cleaner and reduce wear.

The manual recommends to clean the air cleaner every 25 hours, and replace every 150 hours.

Spark plug is to be checked/cleaned every 100 hours, replaced every 200.

Idle speed (governor setting) and valve clearance should be adjusted every 150 hours (0.15mm IN, 0.2mm EX). The valve cover is stamped steel and just uses oil safe rtv as a seal, I use loctite 3900. The Honda GS series engine uses a cast aluminum valve cover and a paper gasket if you were ever so inclined, but the stamped ones work fine.

The GC engines are pretty idiot proof. The cylinders are aluminum sleeved, the rods and crank are aluminum journal bearings. You are correct about there not being an exhaust valve seal, just one on the intake.

The most common problem people have with them is carburetor clogging. On models with an idle circuit the slow jet is hidden under a phillips screw and the hole is around 0.5mm, ethanol clogs it quick and most people don't know it's there. This causes an idle surging condition. Then of course main jets and nozzle clogging, I always recommend E0 fuel when possible.

Sorry for the wall of words, but hopefully this helps.

 

[engineer2]

^ Good writeup!
I love Honda's engine air filter reminder. When my mower's air filter becomes hopelessly clogged, the engine backfires once and blows the filter and the filter cover off. That way you know it's time to buy a new one. A very convenient reminder that you certainly won't forget!