Testing Electrica1 Components - Yamaha MM700A Manual

The troubleshooting procedures described in this chap-
ter provide typical symptoms and logical methods for iso-
lating the cause(s). There may be several ways to solve a
problem, but only a systematic approach will be success-
fill in avoiding wasted time and possibly unnecessary
parts replacement.
Gather as much information as possible to aid in diag-
nosis. Never assume anything and do not overlook the ob-
vious. Check the position of the emergency stop and
tether switches. Learning to recognize symptoms will
make troubleshooting easier. In most cases. expensive and
complicated test equipment is not needed to determine
whether repairs can be performed at home. On the other
hand, be realistic and do not start procedures that are be-
yond the experience and equipment available. Many ser-
vice departments will not take work that involves the
reassembly of damaged or abused equipment. If they do,
expect the cost to be high. If the snowmobile does require
the attention of a professional, describe symptoms and
conditions accurately and fully. The more information a
technician has available, the easier it will be to diagnose
the problem.
Proper lubrication, maintenance and periodic tune-ups
reduce the chance that problems will occur. However,
even with the best of care the snowmobile may require
troubleshooting.
Electrical specifications are listed in Tables 1-3 at the
end of this chapter.
Chapter
Two
Troubleshooting
An engine needs three basics to run properly: correct
(Figure 1). If one basic requirement is missing, the engine
will not run. The ignition system is the weakest link of the
three basics. More problems result from ignition break-
downs than from any other source. Keep that in mind be-
fore tampering with carburetor adjustments.
If the snownlobile has been sitting for any length of
time and refuses to start, check and clean the spark plugs.
If these are good, inspect the fuel delivery system. This in-
cludes the tank, filter, pump and lines. Gasoline deposits
may have blocked carburetor jets and air passages. Gaso-
line tends to lose its potency after standing for long peri-
ods. Condensation may contaminate it with water. Drain
the old gas and try starting with fresh gasoline.
Most parts suppliers do not accept returns on electrical
parts. When testing electrical components, make sure to
perform the test procedures as described in this chapter.
Also make sure the test equipment is working properly. If
a test result shows the component is defective but the
reading is close to the service limit, have the component
tested by a Yamaha dealership to verify the test result be-
fore purchasing a new component.
OPERATING REQUIREMENTS
TESTING ELECTRICAL COMPONENTS