Spark Tester
The spark tester is a handy diagnostic tool available at most auto
stores. The one pictured here not only allows you to check for spark, it
also allows the engine to run while you watch the "fire."
Simply place the spark tester between the lead and the spark plug (as
shown). Remember, this tool does not check the condition of the spark
plug. It does, however, show if steady fire is available to the plug.
Many times it is difficult to troubleshoot a small engine that is not
running properly. Both a carburetor problem and "fire" breaking down
make an engine act the same way. With this tool, you can see a spark
breaking down through the window on the tester. The spark tester is much
cheaper than buying a new starter or battery or getting a recoil starter
rewound.
Carburetor Fix
The carburetor is the No. 1 cause of modern small-engine problems. The
orifices in these carbs are small; so clean, fresh fuel is critical.
Two basic types of carbs can be found on small engines� �� ��the bowl and the
diaphragm. The bowl type is usually used on equipment, such as a lawn
mower, where the engine is operated in more of a fixed vertical
position. The diaphragm application allows the engine (usually a
two-stroke cycle) on equipment, such as a line trimmer or chain saw, to
run in any position and not flood the engine or leak fuel.
Many modern bowl-type carbs have fixed jets with no adjustments. This
arrangement should allow for clean burning. Some have an adjustment on
the idle mixture. Remember, this adjustment sets the amount of the fuel
mixture but not the ratio of the mixture. A thorough cleaning of the
bowl carb and a new needle and seat usually will work.
The adjustable diaphragm carb is trickier. The gaskets and diaphragms
must be replaced properly when you install a new carb kit after cleaning
the carb. On the end of the carb with four screws, the diaphragm goes
out and the gasket goes toward the carb. On the other end, the diaphragm
goes next to the carb and the gasket goes out. In either case� �� ��bowl or
diaphragm� �� ��disassemble the carb, soak it in cleaner and blow all
passages with air. Then install the new carb kit, setting the high side
about 2 1/2 turns out and the low side out about 1 1/2 turns. After the
engine starts and warms up, do your final carb adjustments.
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A cleaned and adjusted carburetor is vital to a smooth-running engine.
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