Storing Lawnmowers
Your lawnmower requires care and maintenance just like any other gas operated engines. To store your lawnmower for the winter it is important to
deal with the fuel in the gas tank and carburetor. Fuel left for several months will deteriorate and possibly not support combustion. The fuel sitting in
the carburetor can turn into “goop” which can plug up small fuel jets inside the carburetor preventing fuel from reaching the combustion chamber,
and if it does, it can coat the spark plug with an oily substance which will “short” it out preventing any spark from happening. Stale gasoline smells
like varnish or paint.
If this happens you can try removing the spark plug, clean it thoroughly and pour about a thimble full of clean new fuel directly into the combustion
chamber. Take all safety precautions when handling gasoline. Replace the sparkplug, choke on full, hook up the sparkplug wire and give the starting
rope a quick pull. If the engine “fires” up, it may be enough to purge the old fuel from the system and combustion chamber, otherwise the carburetor
will have to be dealt with. If the motor starts slowly move the choke into the full open position, and let run for a few minutes.
At the end of the season and the lawn mower has a shut-off valve on the fuel line, turn off the valve and run the engine until it quits. This
will assure all the fuel is used up in the carburetor before storing. The fuel in the tank will possibly be ok if it is topped up, but if you want to be sure
then add a little fuel stabilizer before storing. If the lawnmower has no shut off valve on the fuel line, consider having one installed, otherwise drain
the tank and run the engine until it uses all the fuel before storing. A meat basting kitchen tool works well for sucking up small amounts of fuel from
the gasoline tank. These can be found in most dollar stores, metal ones are best, keep in your tool box and only use it for this purpose, and you don't want it to end up in the kitchen. Remove the spark plug and squirt some oil into the sparkplug hole. Replace spark plug and spark plug wire.
Checking Level Of Oil
Check the oil level before operating the lawnmower. Place the lawnmower on a level surface to get a true reading. Oil dip sticks usually have a low
mark and a full mark. Top up to the full mark. When checking the level screw out the dipstick wipe it off with a clean rag and then just dip it into the
oil fill hole, remove and check level (don't screw it in each time). The engine needs a proper level of oil to help cool the engine; a too low level can
lead to overheating. A too high level can reduce power.
If the engine doesn't have a dip stick, then clean around the fill plug, remove and top up the oil to the fill level.
Condition Of Oil
Check the oil on the dipstick for color and condition. Oil in good condition is clear, light brown in color. Oil in bad condition is black in color and has a
dirty look.
Changing Oil
In the spring the oil should be changed. There is a drain plug somewhere on the lower part of the engine; remove it and drain the oil into a
pan and take it to a recycle depot when you can. If the engine doesn't have a drain plug, then tip the lawnmower on its side and drain the oil out
the filler hole while the engine is still Hot. Hot oil picks up dirt and suspends it so it can be drained with the oil. When the oil is cold, dirt drop away
from the oil and piles up in the engine. Wear eye protection so you don't get splashed in the eyes and keep hands away from the oil as it is very
hot. Replace the plug and refill with new oil, using 10-30 or whatever the manufacturer recommends. Most engines will not take a full liter of oil, so
stop and check the level several times. Overfilling is not good for the engine, the rotating crankshaft will hit into the overfilled oil level, throwing up a
lot of oil. The engine will run rough and it can cause more oil than needed to reach the combustion chamber resulting in poor combustion and a lot of
blue smoke. Burning oil in the combustion chamber leads to a fouled spark plug and a build-up of carbon on the piston head; this can cause
"dieseling" (engine continues to run after it is shut off). If a build-up of carbon takes place, the head will need to be removed in order to scrape
away the carbon away from the combustion chamber and the top of the piston. A new head gasket would also be necessary when replacing the
head. The head bolts need to be tightened in a criss-cross fashion (first one bolt on one side, then on the other side) they need to be torgued to
the same tightness (torgue wrench works best).
Spark Plugs
The correct size spark plug must be used. If the spark plug is too long, the end could hit the top of the piston resulting in damage. If the spark plug
is too short, it could result in miss-fires.
Keep in mind that the spark plug in place might be the wrong size as somebody could have changed it wrongly. Check the specs for the correct
spark plug. Spark plugs are not too expensive and should be changed once a year. They can also be maintained by removing the spark plug and scraping off the carbon. Use a fine screwdriver to get down deep on the sides of the electrode and finish up with a wire brush overall. Check the spark gap and reset if necessary. A common gap is .030
Cleaning Air Filter
You need to clean the air filter at least once a year as it does get plugged up with grass and dust. As it picks up dirt, it acts like the choke
is on, drawing in more fuel and less air making for a bad mix. You need a clean filter for a smooth running engine. The air cleaner is located near the
front of the engine, attached to the carburetor, behind some sort of cover (usually located on the left front side - looking from the back side)
which is designed to be easily removed. Remove the cover and filter, brush out the larger particles with a paint brush. Then with a vacuum cleaner,
vacuum out the filter. You can clean the air filter several times before it needs replacing, and if you're careful, it may last the life of the lawnmower.
Replace the filter and cover.
Sharpening Cutting Blade
The cutting blade will need sharpening. Before working on this, remove the spark plug wire and make sure the controls are in the off
position. If the lawnmower has a type of built-in wind-up spring, start action, be sure to discarge it before working on the lawnmower. Turn the lawn mower on its side, just enough to get at the bolts holding the blade in place. Do not turn the lawnmower right over as this allows oil in the rankcase to slip past the piston into the combustion chamber. Take a good look at how the blade is held in place, as there may be two or three pieces involved and you will have to know how to reassemble it (you could mark each piece with a marker pen). Remove the bolt/bolts and cutting blade. This would be a good time to scrape out all the dirt and grass accumulated onto the metal frame. A big screw driver will work well for doing this. Take the cutting blade and sharpen it with a file or electric grinder. Sharpen to 30 degrees. Follow the original pattern; you only need to sharpen the tips (approx. one-two inches). Take the blade and using something round like a Philips screwdriver in the center of the blade or a nail pounded into a post or wall, balance the blade. If the blade appears off balance (will not stay horizontal) file/grind a little more off the heavy side opposite the cutting edge. A quick touch up usually does not change the balance. Reassemble the blade to the lawnmower and tighten securely. Re-check tightness again after first use. Re-connect the sparkplug wire. If you are in doubt which way the blade goes, keep in mind that the sharpened tip will be the lowest point and will be positioned so as the arm rotates the grass will be thrown upward.
Top up the fuel and your ready to go!
Removing a Seized/Rusted Blade Bolt
Tho remove a seized bolt, tap the end of the bolt straight on, with a hammer several times; this will help release the bolt thread. Add a couple drops of penetrating oil to the bolt shaft, wait a few minutes and remove bolt. Take note of how the bolt , blade and other parts go together, so you will know the proper order in putting it back together.
Starting Lawnmower
Place the lawnmower on level ground or sidewalk, not on lawn where blade can contact high grass. Check the level of oil and add some if necessary.
Turn the fuel shutoff valve to fully on (only if the lawnmower has a shutoff valve). Shift the starting lever to full start position; this will also turn
the choke to fully on. Give the rope a couple of pulls, until the engine attempts to start. Then move the start lever so the choke is off or you may
end up flooding the engine with fuel. Give the rope a couple more pulls until the engine starts, then move the choke about half on until the engine
warms up a bit, then you can move the lever so the choke is completely off. If the engine has a choke separate from the start control, then operate
the two to get the same result.
Lawnmower Starts But Runs Rough
If your lawnmower starts but runs rough, check to see that the manual choke is fully open, providing your lawnmower has a manual choke; some
lawnmowers don't have one. The other common fault is a plugged up air cleaner which acts like a choke that is closed. Either one of these two
conditions will cause an engine to run rough because of the wrong mix of fuel and air to the combustion chamber. To clean the air filter, open the
cover to the air cleaner assembly which is located next to the carburetor. The cover is either a snap on type, or has one screw holding it on.
Remove this and remove the foam filter. Brush off the grime and vacuum out the dirt, if an engine is run for long period under this
condition the spark plug will become carbonized up and will add to the rough running of the engine. Clean or change the spark plug.
No Spark - Won't Start
Always try a new spark plug first before any test. The most common problem when there is no spark, is the off control switch mechanism. When you
slide the off switch devise to the off position, a mechanical arm (this is situated near the carburetor) swings over and shorts out a wire that goes to
the magneto device. If the sliding arm goes out of adjustment it will short out the wire when it shouldn't. Check to make sure the sliding arm is free
from shorting out the wire to the magneto, when the controls are in the run position. Also if the coating of the wire of the magneto unit becomes
damaged, it will short out the magneto wire to the metal of the engine and no spark will take place. The sliding shut off control must be adjusted
correctly or you may not be able to start the engine or it may not shut down the engine either. A bent key in the keyway will change the timing of the engine and may prevent an engine from starting; this can happen by hitting a rock or some solid object on the lawn while cutting.
Bag Care
If you are using a bag to catch grass on your lawnmower, the bag has to be able to "breathe" to work properly. To get the proper suction and action to lift the grass from the blade the moving air must be allowed to move freely through the bag. The bag fabric will impact with debris over time, take a hose and thoroughly wash the bag as needed.
Engine Care
Combustion engines need air to cool. Regularly remove debris from the cooling system vents. Overheating can destroy the engine
Getting More Power Out Of The Lawnmower Engine
You can get top power out of your lawnmower engine by changing the oil on a regular basis; cleaner oil, less friction. Keep the cutting blade sharp;
a dull blade robs your engine of power. Keep the air cleaner clean; lack of air and the engine will not perform at its peak. Correct adjustment of low
and high speed carburetor adjustments; proper fuel air-mixture creates the most power within the combustion chamber. Clean or new sparkplug;
helps give a complete combustion for added power. Keep the engine clean; an over heated engine loses power. Use clean new fuel; stale fuel does not produce full power.
Lawnmower Runs A Short Time, Then Quits
The fuel tank lid has a vent hole to allow air to enter the tank and replace the fuel that is leaving. If the vent hole is
plugged, a vacuum will take place and prevent any fuel from leaving the fuel tank.
Pull Rope - Won't Return
The pull rope is returned by a wound up spring. The reasons for not returning is; broken spring, rusted spring or grim in the spring coil mechanism.
You can try adding a few drops of oil into the spring and working the rope back and forth. If this doesn't work, then the spring has to be removed
and thoroughly cleaned, oiled and replaced. This is not a job for someone who has not done this job before. The spring can fly out and cause injury!
You can unbolt the complete mechanism; this usually is held in place with three bolts. Take the complete unit to a lawnmower repair shop and have
them do the repair.
Pull Rope - Won't Turn Engine Over
If you have had the lawnmower totally upside-down for a while, oil from the crankcase, may have leaked pass the piston and filled the combustion
chamber. The piston has no place to go; therefore the engine appears seized-up. Remove the spark plug and place lawnmower on its side and pull
on the starting rope until all the oil is pumped out; through the sparkplug hole. Add a little fresh fuel into the sparkplug hole and place a fresh
sparkplug into place. With choke off and throttle set to full throttle, start the engine. There will be a lot of blue smoke until the oil is burned
out.
Engine Vibrating
Engine vibration is a condition in which the engine shakes back and forth. Engine vibration can be caused by loose engine mounting bolts. A very
serious condition is a cutting blade bolt coming loose. If this happens, shut the engine down right away, as the blade could come right off and cause
serious injury. Other causes is out of balance cutting blades.
Shutting Engine Down
Allow engine to come to an idle before killing the ignition as unburnt fuel can pass into the exhaust system, igniting and causing a back-fire. Do not
stop an engine by removing the spark wire, as this can cause a high voltage spike in the secondary windings, which may get into the primary
windings where it can damage the coil or solid state components.
Two Stroke Mixture
Some engines use a 32 to 1 mix, others a 50 to 1 mix (50 parts fuel, 1 part oil). Check the owners manual or the fuel tank decal for the correct mix.
Always shake the fuel can after dumping the oil into the fuel.
Determing Right Or Left
Mowers left and right side is determined from standing behind the mower.
Uneven Cutting
If the cutting height is incorrect, the cut will be uneven. To adjust the cutting height, place the lawn mower on a flat surface and check the
heights, front, back and sides.
Check Cutting Blade For Cracks
Hang the blade from its mounting hole and strike it gently with a hammer. A good blade will ring like a bell. A cracked blade will give a thud.
Fairy Ring
If you are cutting the lawn for someone else and they have a lawn infected with fairy ring, dandelion, or anything else that you don't want on your
own lawn, and then remember to wash your lawnmower and wheels with a hose before returning home. It is easy to transport unwanted spores and
seeds with your lawnmower to your own lawn.
Lawnmower And Blue Smoke
Blue smoke is an indication that the engine is burning oil. Check to make sure you haven't overfilled the oil in the crankcase. If the oil hasn't been
changed often enough the rings may have carbonized up and not ate doing their job. Try a chemical approved for this condition. If the engine is very old the rings may be well worn and oil is entering the combustion chamber. Try heavier weight oil, this may help. Always keep the air cleaner free of dirt, grass and grime; a plugged up air cleaner is like running the engine with the choke always on.
Black smoke is an indication of too rich a fuel air mixture.
Engine Surging
Lawnmowers have a device to maintain constant engine speed over different cutting conditions. The way this is accomplished, is by an air driven
control system. The cooling fan for the engine also drives a vane type lever by air pressure, which is linked to the carburetor, to maintain a constant
speed. If the vane gets clogged up with grass, etc. it will not be able to do its job properly. The vane has to be able to move freely, and if it can't,
surging will happen. Cleaning up the mechanism should correct the problem.
How A Choke Works
When you put the controls in the full choke position, a small metal cover closes in the air intake channel,on the outside end of the carburetor between the air cleaner and carbureter. This is part of the carburetor. The purpose is to reduce air and increase fuel, for a richer fuel-air mixture.
This is needed on cold engines, but not required on a warmed up engine. If you leave it in full choke position after the engine is warmed up; the engine will run very rough and will carbon up the spark plug. You can start with a fully closed choke and gradually reduce it as the engine warms up.
A choke does not usually require any maintenance other than setting the adjustment cable, so it closes completely and opens fully.
