Figure 3-45.A typical P-250 pump unit.
For more detailed information concerning
operation, maintenance and repair of the P-250, refer to
the NAVSEA technical manual, Firefighter Pump
P-250 Mod 1, S6225-BW-MM0-010.
Some gasoline engines serve as outboard motors to
power small boats. A high percentage of the motors
problems are electrical. A large number of problems are
also caused by the use of fuel with a lower octane content
than specified by the manufacturer. To gain knowledge
about operating, maintaining, and repairing outboard
motors, review manufacturers service manuals and
assigned PMS publications. Most outboard motor
manufacturers offer a high quality training course, free
of charge.
JACKING GEAR
The Engineman 3, NAVEDTRA 10539, introduced
the two primary types of jacking gear, the ring gear, and
the pinion assembly, and described their use. The only
maintenance required for jacking gear is periodic
inspection for wear and minor lubrication of the moving
parts of the pinion assembly.
FUEL AND OIL PURIFIERS
Specific directions for operating a purifier are given
in the manufacturers instructions provided with the
unit. The following information is general and applies
to both the fuel and the oil purifiers.
For maximum efficiency, purifiers should be
operated at their maximum designed speed and rated
capacity. An exception to operating a purifier at its
designed rated capacity is when the unit is used as a
separator with 9000 series detergent oil. Some engines
using the 9000 series oils are exposed to large quantities
of water. When the oil becomes contaminated with
water, it has a tendency to emulsify. The tendency to
emulsify is most pronounced when the oil is new and
gradually decreases during the first 50 to 75 hours of
engine operation. During this period, the purifier
capacity should be reduced to approximately 80 percent
of its rated capacity.
Most oils used in Navy installations can be heated
to 180°F without damage to the oils. Prolonged heating
at higher temperatures is not recommended because
such oils tend to oxidize at high temperatures. Oxidation
results in rapid deterioration. In general, oil should be
heated enough to produce a viscosity of approximately
90 seconds Saybolt universal (90 SSU), but the
temperature should not exceed 180°F. The following
temperatures are recommended for purifying oils in the
9000 series:
3-46