MJM Yachts LLC 40z, Руководство пользователя

Страница: 44 / 64

Chapter 9 Finishes, Equipment, and Appliances MJM 40z Owner’s Guide page 36
RPMs weren’t effected nor the IPS function (a
wonderfully resilient system!). Subsequently all new
MJMs are being equipped with warp cutters.
Things like discarded plastic Baggies, weeds, etc.,
can also plug up the raw-water intake on the
drives. You can avoid this problem by visually
inspecting the strainer basket. Good water flow
should exist without evidence of lots of air. When
removing debris, be sure to properly replace the
seal, otherwise the pump will lose suction.
Smearing the seal with Vaseline or other marine-
grade grease helps.
No Water Circulation
If upon starting the engine at
idle you don’t see water circulating in the strainer:
(1) Stop the engine, (2) Check to see that both
intake and raw water outgo valves are open at the
drives, (3) Fill the strainer basket container with
water, re-seal the strainer and turn on the engine
again to deal with a possible air lock, (4) race the
engine in neutral momentarily, (5) dive over the side
to see if a plastic bag or other debris is covering
the intake, (6) Inspect the impeller which pumps
water through the engine.
Hard Knocks
Collision with an underwater
obstacle that damages the propulsion system.
Often you can still operate the boat at low RPM to
return to port, being careful to avoid excessive
vibration that might otherwise compound the
damage by damaging the drives. The problem may
be corrected in a day or so without hauling by an
experienced diver who has access to a prop shop
where the blades can be repaired and the prop re-
balanced and recoated with PropSpeed, then re-
installed.
Bad Battery
Marine starting batteries die from old
age and neglect. Keep the terminals and posts
clean from that green corrosion that builds up,
restricting the flow of current – preventing them
from fully charging. Periodically have your batteries
tested to determine their condition and expected
longevity. The 40z is equipped with a “parallel”
switch, which can be turned on to employ the 400
ampere-hour house banks in starting the engine.
Stale Gasoline
Not applicable
Sagging Belt
As V-belts wear, they stretch and
begin to slip. Consequently, alternators and water
pumps don’t spin to their full speed. Batteries may
not fully charge and coolant circulates sluggishly.
The solution is to check belt tension regularly and
tighten belts when necessary. Drive belts can also
snap. The only way to avoid this malady is to
replace them once they begin to show wear.
Some spare belts are provided in the engine
spares kit.
9.2 D
IESEL
O
PERATION
What Diesel Mechanics Wish Every Boat Owner
Knew
The following is edited from an article by Captain
Bernie Weiss at www.AtlanticYachtDelivery.com.
To run well, a diesel engine requires only clean
fuel, clean lubricating oil, coolant, and lots of air.
Below are ten important maintenance issues that
diesel mechanics wish their customers knew:
Don’t baby the engine
Diesels don’t like to idle in
neutral, or even in gear at low speeds; they do like
to work hard under load. Generally, 10% less than
the maximum RPM is the best cruising RPM.
Excessive idling leads to gradual build-up of
detrimental varnish on the cylinders, and deposits
of soot and carbon on the engine’s valves and in
the exhaust system, particularly at the manifold
injection elbow where raw cooling water exiting the
engine mates with the exhaust gases. Run it hard.
However...after running at cruising RPM for several
hours, a brief cool-down at idle speed, with no
load, is beneficial. A few minutes is enough.
Give your engine clean fuel
Fuel is contaminated
when it contains water, sediment, other solids, or
biological organisms, some of which thrive in diesel
fuel. To minimize contamination, don’t store your
boat for the winter or let it sit around for weeks at a
time with fuel tanks only partly full. A full tank
minimizes condensation of water vapor on the
tank’s interior and the growth of microorganisms.
Fuel filters trap sediment, sludge, water and
organic material and should be changed at
periodic intervals.
Be conservative in your estimate of fuel
consumption
When underway, don’t delay
refueling to the point where you have expended
nearly all the fuel in the tank. The last 20% should
be held in reserve. To suck up the last few gallons
is to chance sucking up water (tank condensate),
sludge, and other contaminants - perhaps even air
- into your fuel lines.
Know how to vent (“bleed”) the air out of your
fuel system
Air locks in diesel fuel systems are a
fact of life. The typical diesel fuel system operates
with a lift pump (a vacuum pump) that lifts or sucks
fuel out of the tank, draws it through the pump,