Service Tips 2 and 4 Cylinder Engines 

TOPICS:
1. The First thing....
2. Oil
3. Air Filters
4. Debris
5. Water in Gas
6. Blades
7. Tilting your Machine
8. Stale Gas

The first thing you should do is read all the literature that comes with your lawnmower (or whatever unit you have purchased). There are wonderful tips In that little booklet that none of us seem to want to take the time to read. However, with the way the small engines are changing, the time it takes to read over the booklet can save you some $$$ in repair bills. If you have an older engine, the same tips listed below also apply.

OIL: This sounds like a pain, we know, but check your oil level BEFORE you start your engine - every time! The majority of the engines require SAE 30, heavy duty, detergent oil designed for air-cooled engines. There are some exceptions, so check your book. Why use oil designed for air-cooled engines? Because air-cooled engines tend to run hotter than water-cooled engines (water-cooled engines are really cooled by water AND by air), the oil is designed specifically for high temperature conditions. Certainly many people have used their favorite motor oil in their air-cooled engines and not had a problem. We understand that and do not want to argue the point. We are just passing along the recommendations of the manufacturers and explaining the reasoning behind it.

When is the last time you changed your oil? Although it is recommended every certain amount of hours (varies by manufacturer), everyone's mowing conditions are different. A person with a nice, thick lawn of Bermuda grass may not have to change oil as frequently as someone who has a lawn that is half dirt and half grass. Think of the conditions we put our small engines through! You may not change the oil in your car for months, but you just can't get away with that in a small, air-cooled engine if you want it to last longer than a couple of seasons!

How much oil does your engine take? That varies, but small 3.5 hp engines usually take no more than 20 to 24 ounces - LESS THAN A QUART. Watch this closely. Overfilling your unit can cause lots of problems too! The larger the engine, the more oil - so keep checking your dipstick.

Air Filter: Check your air filter when you are done mowing (or done with the job). You will have a foam filter or a paper filter element. The foam filter can be washed, then set out to dry until next use. The paper element can be banged against a hard object so that all the dirt falls out of it. A paper filter may be surrounded by a piece of foam called a pre-filter. This can be washed like the foam filter.
Here is the tricky part about the foam filter. Many people have heard the trick of putting oil on their foam filter to help catch the fine grains of dirt. IT WORKS - BUT make SURE you only put a FEW (4 to 5) drops of oil on the foam and work it into the foam. DO NOT soak the foam in oil. Air is drawn into the engine through the filter. If the filter is soaked with oil, no air will be able to go through the filter. Let's look at it this way - can you work for very long if you can't breathe? No, and neither can your engine!

What happens when you are eating or drinking and it goes down the wrong way? You choke, cough, or otherwise sputter. right? The same thing happens when your air filter gets so full of dirt and crud that the air flow sucks it down into the carburetor. Your engine will choke, sputter, and not want to work. Replace your air filter after a few cleanings. When your foam filter is falling apart in your hands or the paper filter is the color of apple cider, an air filter replacement is long overdue.
THIS TIP ALSO APPLIES TO 2-CYCLE ENGINES

Debris: Keep your machine free of debris. If grass, dirt, pine straw, or anything else has accumulated around your engine, how can the air get to it to cool it? Would you run around in 100 degree weather with a coat on? Not for long or you would start overheating and possibly get sick. Don't make your small engine work while it is coated with grass, dirt, or other debris. This debris will also hold in moisture and cause your mower deck to rust out prematurely. Riding lawnmower decks are quite expensive ($200.00 average just for the shell). Keep your deck clean, inside and out.
Should you wash your machine with a hose? Lots of pros and cons on that. If it is a small unit and you can make sure to set it out in the sun so it dries, and mop up any puddles of water on it, okay. But on the riding lawnmowers, the disadvantage is that the water settles into the seals and bearings around the pulleys, causing rust and premature wear. Try blowing off debris before attempting to wash it off. Not everyone has compressed air at home, but try a blower, a vacuum with the hose attached to the exhaust, or just a small broom and "elbow grease".

Another disadvantage to washing your machine is the fact that you just might get water into the carburetor. You may think you are far enough away from the carburetor with your hose, but water splashes. Also, you may get your air filter wet - that ruins paper air filters. Water can then seep through the air filter into the carburetor. That is why it it TERRIBLE to leave equipment in the rain or out in the elements. Just ONE DROP of water in the carburetor can stop it up.
THIS TIP ALSO APPLIES TO 2-CYCLE ENGINES.

Water in the gas: How does water get in the gas? One way is by leaving your machine in the rain or storing it outside so the dew settles on it (most gas caps are vented). But it can happen in other ways, also. When is the last time you checked your gas can? Did you ever leave it in the rain or outside all night? How long has it been since you've cleaned it? Is there trash and other debris in the can that could end up in your unit's gas tank and get sucked into the carburetor? Have you ever poured gas into a clear container and added water? Watch what happens. Water is heavier than gas. It will sink to the bottom of the container. Pretend that the container is your gas tank. What is going to get sucked into the carburetor first? (Answer: WATER)Do carburetors work with water in them? (Answer: No!)
THIS TIP ALSO APPLIES TO 2-CYCLE ENGINES

Blades: Check your blades frequently, BUT BE CAREFUL HOW YOU TILT YOUR MACHINE!!! (That will be addressed in the next section.) The better your blade(s), the more efficient your engine will run. A nice sharp blade will cut right through the grass. A dull blade will beat and tear your grass! If your blade is just dull, you can have it sharpened. However, if your blade is worn, change it. Have you ever seen the ends of your blade worn almost in half lengthwise with the metal thin and jagged? If that thin, jagged piece was knocked loose (say you just hit a small rock) on a machine turning over 2000 revolutions per minute, how far will that thin piece of metal travel and will it have enough force to penetrate the eye, skin, heart or lung of a pet, child, or another adult? Sure, it depends on the distance, but the point we are trying to make is -- SAFETY NOTE: WHENEVER YOU INTEND TO WORK ON YOUR BLADE, DISCONNECT YOUR SPARK PLUG WIRE. DO NOT ATTEMPT TO TURN YOUR BLADE UNLESS THE SPARK PLUG WIRE IS DiSCONNECTED.

When you go to buy a new blade, what kind do you buy? Do you buy one designed to fit your machine (Murray, MTD, AYP, Poulan, etc.) or do you buy one of those "universal" kinds with the big hole in the middle? You know, the cheap one, `cause who wants to spend lots of money on just a blade. So you take it home and put that spacer (included in the package) in that big hole to make the hole smaller so it will fit on your lawnmower. Do you have a big washer to put between your blade and your blade bolt, or do you know? Are you absolutely sure that that little spacer is not going to work its way out of that big hole? Are you sure that, at over 2000 r.p.m.s, your blade is secure? Do you want to bet your leg on that? Or maybe your child's life or your pet's life? That is why, on newer nmachines, you will find blades with star patterns or D patterns - so that the proper blade is put on the machine.

Tilting your machine: Look at your engine and imagine it is a box with four sides. On one side will be the carburetor and air filter, on one side will be the spark plug, on one side will be the muffler, and the other side is blank (remember, we are imagining to an extent). You can ONLY tilt your machine on two of the four sides - otherwise, you may run into major problems. What side can be UP when you tilt? The spark plug side or the carburetor side - THAT'S IT! What will happen if you don't keep the carburetor and/or spark plug up? You run the risk of oil dumping into your cylinder, carburetor, or air filter and causing some problems (i.e., your machine might not start, oil will drip out of the muffler, or you won't even be able to pull the rope.)

Stale gas: What happens when you let your equipment sit for a long period of time with gas in it? Well, several things. First you have to understand gas. Gas is formulated differently in the summer than in the winter. If you fill up your engine in August and decide to use it in February, you might find it hard to start. Besides being formulated a little different for weather extremes gas also breaks down over a period of time. When gas breaks down, it also "breaks down" your carburetor parts, so to speak. For as many weather extremes that there are in this country, there are just as many arguments over what to do. In the southern/southeastern part of the country where the weather extremes are not drastic (our location) we have found that using a gas stabilizer (made by a reputable company) is most effective. It not only keeps the gas from breaking down, it also keeps your carburtor parts in good working order. If you are in a part of the country where the weather is extreme, you may want to ask a local, reputable shop what they recommend. It will not hurt to put stabilizer in your gas when you use the machine (thus coating your carburetor diaphragms) then empty your tank before putting the machine away.
THIS TIP ALSO APPLIES TO 2 CYCLE MACHINES. GAS STABILIZER IS DESIGNED TO BE USED IN 2 CYCLE GAS MIX ALSO.