# When to do annual maintenance on mowers



## vancwa (Oct 28, 2021)

I'm sure this topic has been discussed ad-nauseum, so sorry if it's a repeat!

I'm a homeowner, not a landscape pro with about 12k ft of lawn. My normal maintenance on a rotary mower with a 4-stroke engine is to sharpen blades as-needed, usually after 3-4 mows. The annual stuff (oil changes, air filter, oil filter, spark plug) I've always done at the beginning of mowing season in the spring, although I suspect that it doesn't make a lot of difference either way.

I do use only non-ethanol fuel, but don't even bother to drain the gas tank at end of season. I just shut off the fuel petcock and just run the motor until it stops. I've also never pulled the spark plug and put a bit of oil in the cylinder and slowly pulled the starter rope. I've never really had a problem in doing the "start of season" maintenance, but some people swear by doing the annual maintenance at the end of the season after the last mow.

When do you do annual maintenance, and why? Do you bother with using synthetic oil, and non-ethanol fuel?


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## Mightyquinn (Jan 31, 2017)

I usually do mine in the Spring after I have scalped the lawn which tends to be very messy and dusty (Scalping is mainly for bermuda and zoysia so it may not apply to you). All I ever do is change the oil with synthetic motor oil and make sure the air filter gets blown out real good. I rarely ever change the spark plug since I'm not using it all that much to justify it. You could probably do it every 2-4 years and be fine. I was able to find platinum plugs for my Honda engine which gives me much more longevity than standard plugs.

I wouldn't worry too much about when you do it as long as you do it you will be fine. I never drain my gas either and have never had an issue.


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## MasterMech (Sep 24, 2017)

It doesn't matter when so much as if you do the maintenance. Speaking purely from a best practice standpoint, yes, putting the machine up with fresh oil, dry tanks, and a freshly fogged cylinder would be ideal. But many of the steps you mention skipping, are for long term or indefinite storage, rather than the relatively short off-season from mowing. Storage over the cold winter season also tends to create fewer problems than storing over hot, humid summers.


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## MasterMech (Sep 24, 2017)

@Mightyquinn if it weren't for the habitual ritual of replacing spark plugs in a mower engine, most plugs would outlive the engines they are installed in.


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## vancwa (Oct 28, 2021)

MasterMech said:


> @Mightyquinn if it weren't for the habitual ritual of replacing spark plugs in a mower engine, most plugs would outlive the engines they are installed in.


Good point and undoubtedly true. I can't say I replace spark plugs _every_ year, but since I buy 5 or 6 at a time for not much money, I tend to do it out of habit while I'm doing maintenance.


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## MasterMech (Sep 24, 2017)

vancwa said:


> MasterMech said:
> 
> 
> > @Mightyquinn if it weren't for the habitual ritual of replacing spark plugs in a mower engine, most plugs would outlive the engines they are installed in.
> ...


Exactly, not a harmful practice, even if unnecessary. But cheap enough to not matter!


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## Guest (Dec 21, 2021)

I usually run Trufuel in last few gas tank fill ups for the season.


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## BrainBailey (Nov 20, 2019)

I add Stabil everytime I fill my gas cans so I never have to worry about it. I was using exclusively non-ethanol rec fuel as well, but it was causing me to foul plugs on my JD 180 every 3 mows (GX120 engine).

I usually have an annual ritual in the fall where I pull everything out and put it in a line. Then I drain all the oil, do all the refills, and give everything a good bath. The mowers and summer equipment get ran out of fuel. The snowblower gets started up and primed for the winter. It's a fun ritual and makes it easy doing everything at once.


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## Retromower (Jan 28, 2021)

Ive got an electric mower, so once a year I pull the shroud off of the engine and blow all of the grass clippings out. If you dont, eventually the clippings will build under the shrough and it can caused decreased air flow and overheating or even a fire, worse case.
Beyond that, I dont do much; maybe scrape all of the built up clippings off of the underside of the deck.
Back in the days when I had a gas mower, in the fall I would run the engine out of fuel and spray fogging oil into the spark plug hole. Then, in the spring, I would change the oil, replace the air filter and replace the spark plug.
I have to say that I dont not miss the days of owning a gas mower.


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## Shindoman (Apr 22, 2018)

Always change the oil in the fall after last mow. That way it doesn't sit all winter with dirty oil in it.


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## vancwa (Oct 28, 2021)

Retromower said:


> Beyond that, I dont do much...


Yes, one advantage of going the battery route is little maintenace. I abuse my gasser so much, even using as a wood chipper at times - don't think the battery mowers would like to be treated that way! I do several EGO tools but not a mower.


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## Retromower (Jan 28, 2021)

vancwa said:


> Retromower said:
> 
> 
> > Beyond that, I dont do much...
> ...


I do with my Ryobi. Sticks, acorns, walnuts, whatever. It all gets ground up by the Ryobi. Its even got a plastic deck. If I had an electric mower with a steel deck, Id be even less concerned about it.
At the worst, all its going to do is smash the little plastic fan on the bottom of the motor, which is replaceable anyways. Id be far less worried about an electric mower than I ever would with any gas mower that Ive owned.
I mean, the vulnerable parts of an electric mower are protected by an engine shroud and even the battery is hidden under a plastic cover. I dont know how you would ever hurt it.
Ive even hit a small stump with my little Ryobi and it slowed it down for a second and then it spooled right back up. I just look at some of the abuse that electric power tools go through, especially operating in dusty and dirty environments. They thrive in conditions that would destroy any combustion engine.


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## BurtMacklinFBI (Jul 17, 2021)

Shindoman said:


> Always change the oil in the fall after last mow. That way it doesn't sit all winter with dirty oil in it.


I was told when I was young that this is the best practice. Dirty oil sitting all winter will let the sentiment settle and sludge up. Is this true?..... Not sure but certainly sounds plausible. All my yard equipment and motorcycles get stored with fresh oil and filter every fall. I also make sure the tanks are topped off with stabil added as well.


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