Cleaning
First of all, clean the whole body of the mower to ensure that there is not a build up of grass that creates acid and corrosion. This includes around the wheels and the hard to get at corners.
Use a wooden stick or ice pole stick to remove any gunk from the cooling fins. If your machine is water cooled, check the condition of the coolant and top off the reservoir if necessary. Sometimes you might need to use a strong jet of water to clean the radiator's cooling fins. You now have a clean machine to work on and see what needs doing.
Maintenance
Important note: Always disconnect the spark plug before working on a lawn mower.
When working on the lawn mower, do not tip it over. This may cause fluids to leak into the breather and/or air filter. It can also cause, in 4 stroke mowers, the oil to come up into the combustion chamber from the crankcase.
The best way to position a mower for maintenance is to lift it up on to two saw horses so that it stays level. If this is not an option, tip the mower up at the end where the spark plugs are and put a brick or piece of wood underneath to hold it up.
If you have not drained the petrol, the best way to prevent petrol from leaking out of the tank is to remove the fuel cap, place a plastic bag over the opening and replace the gas cap. Ideally all fuel should be removed at the end of the mowing season and fresh fuel added at the start of spring.
Clean out the air filter and also the fuel filter if there is one. Ideally both filters are replaced every twelve months, depending on the amount of use.
Remove the spark plug and inspect them for corrosion and wear. If they are showing some wear, don't try to clean them. It's cheap insurance to simply replace them with new plugs unless they just need a good clean with a wire brush. Be sure to blow away any debris with compressed air before removing the plugs. A few dabs of anti-seize compound or RP7 will ensure easy removal next time.
Particularly at the beginning of spring, tighten the blade nuts and engine mounting bolts, as well as any other nuts, bolts and screws. Replace loose, wobbly wheels. Be sure to keep the drive mechanism on self-propelled mowers in good working order. Check belts and gears for wear and fit.
Blades
If you have not changed your mower blades, it is a good idea to do so. This should be done annually.
Shredded or brown tips of grass blades are an indication of a dull or damaged mower blade. Other signs are an excess vibration or a loose mounting or crankshaft. Do not sharpen rotary mower blades as you will destroy the balance and further endanger the blades, throwing out bits of metal.
Oil and Lubrication
For 4-stroke mowers, change the oil at least once a year.
4-stroke mowers also need their oil levels checked before use and topped up if necessary as insufficient oil can lead to engine seizure.
Lubricate the choke and throttle linkages and apply grease to all the fittings, including the mower deck, the raise and lower mechanism.
If there are grease fittings, check them every couple of months and also the wheels.
Make up a small tin of fuel. With 2 stroke mowers it also helps to put in fuel additive to protect and lengthen the life of the fuel.
Tips
Run your two stroke machines at full power; a lot of people make the mistake of not running the machine at full speed as they’re afraid of damaging the machine. Two stroke machines are designed to work hard and work best when they’re running a full power. Problems will be caused with unspent fuel and carbon build up when the machine is not run at full power.
Mix your 2 stroke fuel mix correctly - don't guess it! It will save you $$$ in the long run.
Give your 2 stroke fuel-can a bit of a shake before refilling your machine as sometimes the oil can settle/separate from the fuel.
Why two different mixes? Easy; it depends on the quality of the oil you use in the mix. If you’re using high quality oil, like Shindaiwa or Echo two stroke oil, it's recommended you run the mix at a 50:1 ratio. Some of the higher quality oils will also have built in fuel stabilizers and smoke reduction formulas etc. This will vary between suppliers. If you’re using another brand of oil or one of lesser quality it's recommended you run the mix at a 25:1 ratio.
The ratios:
50:1 = 100ml of two stroke oil to 5 litres of unleaded petrol
25:1 = 200ml of two stroke oil to 5 litres of unleaded petrol
Four Stroke Fuel: Not much to it really - straight unleaded petrol. Keep an eye on the length of time your store it. Take old fuel down to the council depot for proper disposal.
A half empty can of fuel stored in the shed will expand and contract with the weather and condensation (water) can build up inside the can. The same goes for the fuel tank on your machine for that matter. This means that when you next fill your mower, you will now have water in the fuel tank of the machine too. The carburettors on your machines are not designed to pass water through jets and as little as 1 drop of water will stop your machine from running.
If the mower has had over about 50 hours of use then take it down to the mower shop for a maintenance check to avoid pollution and wearing out of your mower.
David Kirkpatrick
* This information was sourced from '9am with David and Kim
