Last year I didn’t winterize my lawnmower at the end of the season. Shame on me. So I took some extra precautions this year to avoid a $50 lawn mower repair, and got away with it. Here’s what I did.
First, instead of buying the overpriced lawn mower oil from a hardware store, I bought a quart of synthetic 10W-30 motor oil. I also bought a new spark plug. They had both a $2 plug and a higher quality $6 plug, but, this being a lawnmower, I went with the $2 plug, figuring if it can’t run on that I have other problems. I can’t get an air filter locally anymore for my mower’s Tecumseh engine, but I order them from Amazon from time to time and keep several on hand.
As an aside, it’s always best to change the oil in July or so, and either change the filter or at least clear the crud out of it.
Next, I dumped the old gas into a cheap dollar-store plastic tray. Using a funnel, I poured the gas from the tray into my gas can, then into my car. A car can adjust to a gallon of old gas as long as it has some fresh gas in the tank too; a lawnmower can’t. Then I dumped the oil into the same tray, then poured it into a plastic bottle with the funnel and took it to the store for recycling.
What I put in was way too much for everyday use but I wanted to clear the carburetor. Then I primed the pump a few times, figuring if any gunk was in the carburetor, the Marvel Mystery Oil could soften it if I gave it some time. I let that sit while I poured 20 ounces of synthetic 10W-30 into the oil tank, changed the air filter and spark plug, and drove to the gas station. I bought a gallon of 93 octane, which usually has more detergents than the 87 octane I normally use. I came back, filled up the tank, double checked all my connections and caps, then primed the carb. Nervously, I pulled the rope. Nothing, of course. I always get nothing on the first pull of the season. The second pull gave some brief life. The motor sounded like my garbage disposal, belched out some nasty black smoke, and ran for about five seconds, but at least it ran. It did the same thing again on my fifth attempt to start. By about the 10th attempt, it was still belching black smoke and sounded awful, but at least it would run. After a few minutes of just sitting there with it, it sounded smoother, and I attempted to mow to the end of the yard and back with it. It didn’t sound good but it didn’t stall.
Then I mowed the front yard. By the end it sounded OK. I figure it’ll probably be OK for the mowing season now–if a mower is going to fail on me, it generally fails very early. I’ll be sure to add more gas with each mow, to dilute the Marvel Mystery Oil.
I’ve been using synthetic oil and Marvel Mystery Oil on mowers for almost four years, and it definitely helps. Without them, I have trouble keeping a mower running more than about three years. With them, I can keep even the cheap single-season disposable $99 specials running for quite a while. (We generally provide a mower at our rental houses, but never a top-of-the-line one.)