One of the big questions all of us ask when it's time for a new piece of equipment is should I get something new, or take a chance and buy used? Like most things you have to weigh the pro's and con's. If you buy new, you know that it has not been abused (yet) and in most cases it comes with a warranty if you do have problems. If you buy used, the cost is generally much lower, but you don't always know what you are getting.
The cost of equipment can be very discouraging, particularly if you are on a budget. So for many people used is the best option. If you are looking at used equipment here are some tips to help avoid buying someone's problem.
The first step in the buying process is to get your own thinking straight. Not everyone has the same perception of "good shape" or "barely used". So when you are looking at something always take what the owner is saying with at least two grains of salt. Don't be fooled if what you are looking at is shiny and clean. It's amazing what can be done with a pressure washer and some Armor-all.
I always start by looking at the tires (if it has tires that is). Tires and wheels will tell you allot about how something has been used. Bald tires is a dead give away that the equipment has been through the ringer. Believe it or not, weather checked tires (with lots of tread) can indicate that the thing has been sitting not been used much. Brand new tires on an old machine should set off a red flag. If the tires pass the sniff test move on to the engine. Check the oil; not only are you looking to make sure it actually has oil, but you are also checking the color of the oil. It never ceases to amaze me how many people simply do not change the oil on their equipment. We often get customers that will tell me they have never changed their oil or done any maintenance but are proud of how good their equipment still works. If the oil is significantly low (like not showing on the dip-stick) run the other way. Chances are the engine has already suffered internal damage and premature wear. If it does have sufficient oil then you should be looking at the color of the oil. Most motor oils are a honey color when they go in. Depending on the brand that color can range from a very light, almost clear, amber to a darker raw honey color. If the oil on the dipstick is in this range then it's fairly new. But, if the oil is very black that means it is old and probably has not been changed in a very long time. Unless you are getting a really good deal, you should probably walk away and find something better. If the oil color is somewhere in between rub a little between your fingers it should still feel slippery and not gritty. Smell the oil (I know sounds weird) if it smells like gasoline there is a problem, most likely the carburetor needs some attention. Any grit in the oil means that you should be moving on to something else.
Once you have satisfied yourself that this particular machine may be the one, start it up and listen. This can be a little tough if you don't know what you are listening for, but give it a try. A worn engine will often make rattling/knocking noises at first that go away after a few seconds as the engine warms up. This is not automatically a deal breaker, but it should be something that you note when negotiating price. If the knocking does not clear up on it's own the engine may not be long for this world. Along with listening you should also be looking when the engine first starts. Keep an eye out for smoke coming from the exhaust. Blue smoke indicates oil, black smoke fuel and white is coolant. A little blue smoke at start-up is generally nothing to get excited about, but if it lasts more than one or two seconds that's an indicator of engine wear. Continuous black smoke means there is a fuel related issue. White smoke that doesn't go away (assuming it's not 10 degrees) can mean it's had serious cooling system failure.
Once you feel somewhat confident about the general health of the engine and machine make sure to test it. Not just for a few seconds; make sure to run it long enough to get it completely warmed up. If possible, use it for it's intended purpose for several minutes. Make sure everything works. Remember you are paying for this thing and it doesn't come with a warranty. If the owner is not willing to let you run it for a few minutes you should be concerned. If someone is selling a piece of equipment they are not doing you a favor by letting you test it out. Once the money changes hands you own whatever problems the machine has.
Finally, once you get your new purchase home I always recommend doing a full service. Change all the fluids, filters, etc. Routine maintenance is the key to machine longevity. By servicing it right away you know when it's due for it's next service and you know that it has the proper fluids and filters. The bottom line is maintenance will always be cheaper than fixing. By doing a service before you use it you know where you stand and you decrease the chance of premature failure from neglect.