SUMMER 2013 | MARINE TECHNICIAN TODAY
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lead. The warning horn should sound. On System Check gauges, the
overheat LED will illuminate but the buzzer will not activate unless the
motor is running. It is wise to test oil pressure switches and water-in-
filter sensors if equipped per the service manual. Digital dash gauges
may have different procedures.
FUEL and OIL
Using a clean glass jar to inspect a fuel sample from the engine. It
should be clean and clear with no debris, water or varnish smell. A
turkey-baster works well for sampling the bottom of a remote oil
tanks for sludge, water, or gelled oil. The engine mounted tanks on V4
and V6 Yamahas collect condensation in a 2” clear hose and should
be examined regularly. Suzuki and Yamaha recommend the annual
replacement of the oil filter assembly between the tank and the oil pump.
Replace and/or clean all boat mounted and motor mounted filters. If
there is no boat mounted fuel-water separator, suggest one for your
customer and emphasize its importance with today’s ethanol fuels
which attract moisture. Pour the correct amount of a fuel additive
into the gas tank to help clean out the system and to stabilize the fuel.
This is very important if ethanol E-10 gasoline is used. Inspect the
condition of the hoses, clamps, and any fuel valves.
ELECTRICAL SYSTEM
Use an ammeter in conjunction with a voltmeter to test the electrical
system. Crank the engine for about 15 seconds with the kill switch
removed. A healthy battery will show 10 volts or more during cranking
or test it with a quality load tester. Make sure the battery terminals
and cable ends are shiny clean and replace any wing-nuts with regular
nuts and lock-washers for secure connections. Distilled water is
recommended for topping off regular batteries. According to ABYC
standards the positive terminals should be protected with vinyl covers
if the battery is not mounted in a covered box and the battery is to be
securely tied down so it will not move around in rough water.
Start the motor and monitor an inductive ammeter to read the charging
output. Compare the results with the service manual specifications.
On computer controlled outboards, download an engine report from
the ECU and save it with the customer service records. Technically-
oriented owners may want a copy for themselves. Check for any error
codes and correct any recent abnormal indications.
TIMING and TEMPERATURE
Set the carb-pickup timing or engine idle timing according to the
service manual in addition to the linkage adjustments. Thermostat
operation can be checked with an infrared temp gun or the finger
method. If you can hold your fingers on top of each cylinder head for
more than 3 full seconds, chances are that the engine is not warming
up enough for proper operation.
CARBON CLEANING
Periodic use of a carbon remover is essential to long outboard life by
keeping the rings and the pistons free of accumulated combustion
byproducts on both 2-stroke and 4-stroke outboards. Cleaners like
Mercury’s Power Tune, Yamaha’s Combustion Cleaner, or Evinrude’s
Engine Tuner have instructions on the can. After waiting the
recommended amount of time, run the engine for at least 15 minutes
at low speed to clean things out before applying full power. Do this
before changing engine oil and filter in a 4-stroke. For even better
cleaning, add the proper quantity of a fuel additive carbon cleaner to
the gas tank according to the manufacturer’s policies.
FINAL ADJUSTMENTS
Idle speed and carb adjustments (if equipped) must be done in the
water for proper exhaust backpressure, not on a hose flusher. Use
an accurate tachometer and be patient while getting everything
“dialed in” perfectly. Some multi-carb and certain EFI engines may
need intake vacuum balancing for a smooth and consistent idle. Do
not overlook valve adjustments that may be required at specified
intervals. Although they are not often part of a regular tune-up, they
are an important procedure affecting the drivability and longevity of a
4-stroke outboard.
Run the boat at all speeds after carefully setting the full throttle timing if
required. Check that the top operating rpm is within the upper half of the
factory recommended range for best performance. By being thorough
about engine service once a year or every 100 hours, or as needed, you
are assuring your customer of a good running, safe, and dependable
motor. Satisfied repeat customers mean more money, a solid reputation,
and job security for you and the business. Be a professional.
B.G.
TODAY’S TECHNICIAN
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