• Small engines need tuneups on a regular basis.lawnmower image by sumos from Fotolia.com
  
  A small engine is a complex mechanism, and things can and do go wrong. When something goes wrong, the engine will be hard to start, sputter, lose power or stall out. By using some simple diagnostic techniques, you will be able to repair a small engine, restoring it to its former like-new glory.
  
  

Start Simple

• When an engine starts under performing, look to the simple things first. Check or replace the oil if it's a four-cycle engine. Look at the fuel filter located inside the gas tank to make sure its not clogged. Examine the air filter as these are notorious for clogging. Look at the fuel itself, ensuring it is clean and not full of lawn clippings or other debris. Pull the spark plug. If any one of these is dirty, clogged, or the plug is fouled, repair and replace accordingly.
  
  If a bad part is replaced and the engine will still not run, the problem is advanced and will require specialist expertise to repair. If it's a two-cycle engine, replace the old fuel with new fuel-oil mix.
  
  

Clean Area

• If you decide to rebuild the carburetor, a clean, well-lit work area is essential. Remove the carburetor from the engine and lay it down on a white towel or large rag. When taking it apart, be very careful as small parts may be spring-loaded and shoot out when you take apart the housing. Before you attempt this, have a rebuild kit with an exploded-view drawing handy, to help with the reassembly process.
  
  

Setting the Idle

• The carburetor idle adjustment may need tuning. If the engine runs but dies out at idling, the idle adjustment screw may have to be turned up slightly. Some carburetors have a fast run and a slow idle adjustment. Adjusting the fast run requires a tachometer, which any good repair facility should have.
  
  

Maintenance

• Any small engine requires preventative maintenance. Briggs and Stratton, a large small engine manufacturer, has specified time intervals for its small engines. One such recommendation is to change the oil every 60 hours of use or at the beginning of every season, whichever comes first. Another recommendation is to change the spark plug after 100 hours of usage. Bob Vila recommends checking and cleaning the air filter often.