Any mechanic will share this bit of news: a piece of machinery left idle will bite its owner if it can. This is especially true of lawnmowers. No, they wont actually bite, but they will refuse to start, they will cut off, smoke, vibrate or cut grass unevenly. Or perhaps they wont cut at all.
Obviously, one can take the unit to the lawnmower repair specialists, but the grass grows on relentlessly meanwhile, and it can be several weeks before the mower is fixed (every lawnmower repair shop is inundated with faulty units these days). Therefore, since the lawnmower repair shop isn't the quick or easy (or inexpensive) answer, there are some steps one can take for basic lawnmower repair as a do-it-yourself project.
Caring for lawnmowers is fairly essential, and its surprising how many owners don't bother, but instead neglect the machine to the point where it needs repairs without even being operated. However, there are only three basic reasons a lawnmower wont operate:
Improper fuel: one should never use Ethanol-based gasoline, as that eats away at a lawnmowers workings (ethanol destroys rubber elements). Its recommended that one use a 93 octane rated fuel; its has more slickness to it, which means it will work its way quickly through the system and not corrode rubber. If the mower will sit idle for the winter, run it until the fuel is exhausted rather than leave it in the mower.
Engine maintenance: in the Internet age, theres no excuse for not knowing the basic repairs for anything; any YouTube video will give basic tutorials on engine maintenance. Often, the problem will be the engine oil (which may need to be drained and replaced, as it is too easily burned through the system10W, for example, is far too low for a lawnmower). One can also easily learn the basic functions of the brake cable and how it connects to the starters function (the main reason a lawnmower jams). Free the brake cable and one frees the starter.
Parts: the most frequently replaced part on a lawnmower is the carburetor, which runs around $50 to $70 to replace; it may, however, just need to be cleaned out, since debris and old fuel can collect inside the carburetor gaskets.
Speaking of parts, this is perhaps the most extensive problem, and deserves a bit more space. We are now leaving the do-it-yourself realm, in other words.
Cleaning the gaskets of the lawnmowers carburetor is quite simple, but this is one time an experienced mechanic should be involved, as the fuel tank must be disconnected.
The mechanic can also remove, test and replace faulty spark plugs these can damage and rust easily by just sitting idle, and they may be so weak that it produces only a faint spark or no spark at all. This test/replacement can all be done by the professional, although most mowers have spark plugs that are easily accessible, and thus replaceable by the homeowner himself (in the rare cases where housing covers the motor and prevents access to the plugs, the mechanic should repair the unit). New plugs are quite inexpensive, either way.
Finally, before one completely turns the machine over to the lawnmower repair professional, the owner can also clean out the air filter this can easily clog with weeds, grass and debris, and lead to a non-starting or choking mower. The air filter is also usually accessible to the owner, and can be inexpensively replaced.
If the owners do-it-yourself repair and maintenance is not enough, and a visit to a professional is in order, one should get a repair estimate. If that estimate is hundreds of dollars, its best to simply purchase a new lawnmower.
Lawnmowers with that large a repair bill are best replaced entirely.