When looking at buying a second-hand lawn mower, consider firstly whether 2-stroke or 4-stroke would more suit your circumstances. Two-stroke machines, for example, don’t need to have their oil changed, while four-stroke machines tend to be quieter, have more torque, and run on normal motor vehicle fuel. For this guide, we will only look at 4-stroke machines, with specific reference to Honda machines, though the principles remain the same for ALL push mowers.
Remember one simple principle when buying a second hand lawn mower:
If it LOOKS misused, abused, neglected, beaten, thrashed, or really second hand, chances are IT IS! (regardless of whether it’s the current model, and regardless of the seller’s reasons for the machine looking the way it does)
As a mowing contractor, I can tell you that the average home-owner lawn mower is used about 20 times a year, while a professional will do up to 25-30 jobs A DAY. If a mowing contractor disposes of a lawn mower after just 12 months, it is the equivalent of an 800 year old machine (taking winter into consideration, but not attention to service intervals). So when buying a lawn mower in an auction format situation, where using the machine prior to bidding is not an option, pay careful attention to the following points, and take caution:
1. BODY DAMAGE
If the engine or body has dents in it, or the chassis has dents, paint missing, cracks, or stickers missing. Cracks in the chassis could be an Occupational Health & Safety matter (OH&S).
2. SUN & WATER DAMAGE
If the engine or chassis look faded by comparison to a new machine, or rusty, or oxidising in parts. Some contractors, and even large home or farm owners, leave their machines in the weather – this will generally shorten the life of the machine and speaks to the overall care and maintenance of the unit.
3. AXLE FREEPLAY
If either the front or rear axle wobbles, or is loose, or is able to slide side to side, it is likely the machine has done a LOT of work, has been misused, or has been handled incorrectly on stairs.
4. MISSING PARTS
Have a brochure of a new machine available and compare external missing parts such as hub caps, height adjusting handle covers, starter rope handle covers, handle bar knobs, stickers, mud flaps, logos, and handles. Don’t be afraid to ask for more photos if in doubt.
5. CATCHER DAMAGE
Look at the inside of the catcher and see if metal parts are bent or missing, whether the plastic is cracked, or whether there are holes or serious abrasions.
IF THE MACHINE IS PRESENT
6. OIL AND SMOKE
Check the oil colour and levels. The oil should be at the correct point on the dip stick AFTER wiping it clean with a cloth and re-inserting. Start the machine and see if it smokes after 2 mins of running. Hondas will sometimes smoke at start-up (even new ones), so keep it running for 2 mins to see if it stops smoking.
7. THE ENGINE
The golden rule on how an engine works relates to how to make a fire: fuel, air, ignition.
If a mower is running rough or won’t start check these things first.
Check that there is fuel in the tank. If the mower won’t start and the fuel is more than a week old, or you are not sure that the liquid in the tank is the right fuel, drain the tank and refill it with fresh fuel.
Check the air filter. Most 4-stroke machines have a 2 stage air filter; a sponge outer filament with a paper inner filament. The sponge outer filament, if dirty, should be cleaned in soapy water when dry mounted, or in petrol if a light film of oil was used to trap more dust. The paper inner filament should be replaced rather than cleaned. The paper filament is made up of V-shaped card like this VVVVVVVVVVVV. Dirt is trapped at the bottom of the ripples and removing the dirt can lead to small quantities going onto the engine side of the filter – this puts dirt into your engine. The best way to clean a paper filament, then, is not by tapping or blowing, but by using a vacuum cleaner. If the dirt is quite heavily caked in the bottom of the ripples, replace the filter. Ideally, just clean the sponge filament more often to keep the dirt out of the paper filament. Before putting the air filter back onto the engine, put a small amount of clean engine oil around the rubber seals of the air filter and a small amount into the sponge outer filament – wring out the excess from the sponge filament.
(c) SPARK PLUG
Have a new spark plug on hand. Compare a new spark plug with the one that is in the machine by removing the used one from the mower. If the used plug is excessively black, or has a build-up of grey or white material around the end that goes in the engine, it may be a case of either replacing the plug or cleaning the existing plug with a wire brush.
(d) FUEL AGAIN
If the first 3 steps didn’t result in the engine starting, use a torch to examine the strainer at the bottom of the tank. If the strainer is full or getting full, replace it. If the mower has an in-line filter (typically on larger engines), and it looks as though it is getting darker or full of dirt, replace it.
There could also be a problem with water or other contaminants in the carburettor float chamber. Turn off the fuel, unscrew the plug at the bottom of the carburettor, and drain the contents (if you don’t turn off the fuel you will empty the fuel tank). Slightly tipping the machine may assist in removing every last drop of water or gunk through the drain hole.
Turn the fuel back on to fill the float chamber and attempt to restart.
If steps 1 – 4 don’t have the engine running, don’t buy the machine and lodge a "Not as Described" dispute with eBay. Chances are it’s a much more serious problem which will take a lot more time to investigate. At this point, if I am the owner of a machine like this, it is usually cheaper for me to drop the machine off at my favourite mower store for a diagnosis/quote.
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