Maintaining a lawnmower

I was mowing my [dad’s] lawn today now into the lee months of the lawn-mowing season. I always check the engine oil before starting. We have the oil changed, blade sharpened, spark plug changed, air filter, etc etc. once a year i.e. in the spring.

I was just wondering if the oil needs to be changed more? This is just a carbureted push mower, don’t know if these engines are 2 or 4 stroke? Anyway I just want our lawnmower to last us many more good years. Thanks

You appear to be doing the right things. You shoulsd also clean or replace the air filter on a regular basis.

If you have oil to change, it’s a 4 stroke. If you have to mix the gas and oil, it’s a 2 stroke. When to change the oil depends on how many hours you run the engine. I’ve seen suggestions from every 25 to every 50 hours. It’s best to check your manual.

The only other thing I would do is add some Stabil to your fuel and run the engine long enough for it to run through the carb before you store it for the off season.

If your are changing the oil, your mower has a 4 stroke engine. I have two push mowers that I am still using. One was made in 1988 and the other in 1992. I change the oil, air filter and spark plug at the end of the season and sharpen the blade. I pour a couple of teaspoons of oil in the cylinder through the spark plug hole and turn the engine over until I can feel that the valves are closed. I fill the gasoline tank to the brim with gasoline that has stabilizer mixed with it. In the spring, I remove the plug and turn the engine over. I then replace the plug and start mowing.

One thing that is important is to clean the mower deck underneath. If the deck is steel, this will slow down rust-out. The decks on my mowers are cast aluminum, but I clean them well anyway. Also, I put straight 30 weight oil in the crankcase. The manual with the mower calls for this in the summer months and I don’t mow in the winter. Multi-visocsity oil doesn’t seem to be as good for these engines, at least in the mowing season.

Good point. I didn’t think about cleaning the deck. It would be a good idea to grease or oil the wheels too.

One more thing–I only maintain the mowers because if they fall apart due to negligence, I’ll be mowing with a reel mower with no engine according to my wife. This removes the threat of me filling the crankcase with the fluid that is used in the trade-ins on the “Cash for Clunkers” program even though I hate to mow. (Actually, I don’t like seeing any engine needlessly destroyed whether it is an automobile engine or a mower engine. A colleague traded a nice 1991 Chevrolet shortbed pick-up for a Toyota RAV-4 on the cash for clunkers program. His Chevrolet pick-up had 130,000 miles, but ran well. I would have bought it had I known).

If you want to see a waste, go over to YouTube and search “cash for clunkers engine”. There are quite a few videos of dealerships destroying engines in traded in cars with sodium silicate as required by the program. Such a shame.

Here’s a 1998 Jaguar XJ8 getting destroyed. Even the mechanics feel bad…

And here’s a Maserati…

I think for the small push mowers, the book will say 25 hours of operation but read the manual. I always changes oil in the fall so it doesn’t sit around all winter with old oil and is ready to go in the spring again. Oil, Stabil in the gas, spark plug, air filter, etc. will keep it going. If its a Briggs engine, you may need to change the carb diaphram every couple years. They are only a dollar or two but need to pay attention while doing it.

You’re doing great with the oil change and general maintenance schedule.

A few suggestion:

At the end of each season, drain the gas tank and run all the gas out of the lines. To do this, just start the engine and run it 'til it stops.

Add about 1 oz of carb or injector cleaner to every gallon of gas in your gas can. I started this years ago and it really does make a difference in the operation of small 4-stroke engines.

It sounds like you are doing the right things. I do all those things twice a year, but I live in northern Florida where the mowing season is longer.

Like Mountainbike, I also drain and burn any remaining gas at the end of the season. If you leave fuel in the tank, you are more likely to need a carb rebuild in the spring.

The worst results happen when maintenance is never done. If you have to pay for the work, once a year is great. If you have to put oil in the gasoline, it’s a two cycle (stroke). If it goes in a crankcase, it’s four.

As for the oil…I too change the oil every spring and fall. Leaving the bearings to sit in bad oil all winter is not very good for them. In the fall I drain the oil…replace the filter (mower has a pressure oil system) and then start it up and run for about a minute to circulate the oil before I store it away for the winter. Then in the spring I’ll change the oil again. May be a little wasteful, but we’re only talking 1 quart here. I also use full synthetic.

My lawnmower (and snowblower) has a fuel cut-off valve. What I usually do is turn that off and then start the engine until it dies…that way all the gas is out of the carb.

Great, my next question is would it be helpful to store this thing in the warm[er] basement rather than the outdoor utility shed this winter? Also if I had some fuel-stabil stuff to my gas canister (damn near full) will it still be good to go in the spring? Not that i’m terribly worried about $5 worth of gas, was just wondering.

I don’t think where you store it would matter as long as its been winterized. And start out next year with fresh fuel. Dump the gas canister in your car.

Outdoor utility shed is great.

My garage is amsll…and full…so I bought a steel washtub and flip it upside down over the mower’s motor. It does the trick. It actually covers most of the mower. Metal does not benefit from being kept warm. It benefits from being kept dry.

Running it out of gas does NOT remove all gas and with out stay built in the fuel it will gum up, maybe not as bad if you do not drain but it will.
Put plastic down under mower, it helps keep moisture away from mower.
Oil is cheap,change at start, once during and at the end.

Drain the gas or use stabil-your choice sharpen the blade,change the oil,all good, but if you are doing your own maintenance don’t bother changing the plug if it starts easily and runs well. I have a 1972 Airens snowblower that will still walk through a 4 to 5 foot deep back yard to make paths for the dog and I have only changed the plug once.

Been storing mowers in a shed for years…same with my snow-blowers. Never a problem.