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Laing's Newsletter January 2005Welcome to the January 2005 issue of OUTBOARD NEWS, an electronic newsletter for the outboard enthusiast.
INDUSTRY NEWS As
we enter the new year, it is interesting to note the different
directions the domestic outboard manufacturers are moving in. There are
three names, and three different philosophies of how the meet the needs
of boaters in the future. Here is a rundown of the three: Mercury
will be taking the four stroke route entirely by developing new and
sophisticated designs to gradually replace their two strokes. The
Verado, which is a 6 cylinder in line four stroke with supercharging,
aftercooling, and digital throttle and shift, will begin to replace the
popular Optimax direct injected two strokes. The Verado is available
in 200, 225, 250 and 275 HP for 2005. In 2006, the Verado line will
include a 135, 150, and 175 HP four cylinder engine. In recent years,
some of Mercury's larger V-block four strokes had components made by
Yamaha. This will be ending, as Mercury terminates a relationship with
Yamaha that dates back at least 30 years. By 2008, all the Mercury two
strokes will be gone. Evinrude
is staking their future on the continuation of two stroke technology.
They are convinced that their new E-Tec technology will prove superior
to four strokes. They have added a 3.3 liter V-6 E-Tec that puts out
200, 225 and 250 HP. The E-Tec spans the range of 60 to 250 HP, and
will soon debut in the low HP segment of the market. They claim the
E-Tecs are lighter, simpler, cleaner, and just as quiet as any four
stroke. Johnson's
future intentions are somewhat cloudier. Johnson's line-up of motors
is divided between four strokes and old technology carbureted two
strokes. The four strokes are all being manufactured by Suzuki. The 8
HP four stroke has been dropped, which was the last OMC designed four
stroke in the line. Since all carbureted two strokes must be gone in a
few years to satisfy the anti-pollution regulations, Johnson will not
be left with much. I
think Evinrude will do well, because there will always be a demand for
a two stroke outboard. Mercury will have a difficult time competing
with the foreign motors, who have more experience in four strokes, but
I think their reputation and name will carry them through. Johnson's
future is a little less certain, unless they have some new technology
in the works. SERVICE One
of the most common service questions asked is about propellers. We
will start this month with some propeller basics: Pitch and diameter. Props
are identified by their diameter and pitch. When you see a prop marked
13.75x21, the first number refers to the prop's diameter, which is
defined as twice the distance from the center of the hub to the outer
edge of the blade. (measured in inches). The second number designates
the pitch, or the distance the prop will move the boat forward with
each revolution. In this example, the blades will draw a 13.75 inch
diameter circle and the prop will move the boat forward 21 inches each
time it goes around.
In reality, the prop won't move the boat forward 21 inches per
revolution; the actual distance will be somewhat less and the
difference is called prop slip. This is not a bad thing,
because a prop must slip to develop thrust. Prop slip can be as little
as 8 percent for fast, lightweight hulls, and as much as 20 percent for
heavier boats. Engine manufacturers specify a maximum wide-open-throttle
(WOT) rpm limit, or more often, a WOT rpm range. The objective is to
select a prop that allows the engine to rev to this limit or into this
range when operating at WOT while the boat is carrying a typical load.
Pitch is the measurement that most closely controls WOT rpm.
As a general rule and depending on gear ratio, we can expect engine
speed to go up by 100 to 200 rpm for each 1-inch reduction in pitch.
Conversely, for every 1-inch increase, engine speed will fall by 100 to
200 rpm. Keep in mind that engine is not the same as boat speed. Next month: Number of blades HISTORICAL In
the 1950's the race was on for larger and faster outboard motors. The
major manufacturers such as OMC, Mercury and Scott kept adding
cylinders and cubic inches in the HP race, but some, such as Oliver,
took a different approach. In a press release dated April 28, 1958,
Oliver boasts:
"This is another step forward and is an Oliver FIRST in large
horsepower in the industry. It is accomplished through the use of two
of our present field proven Olympus motors with matched counter
rotating propellers. The practical elimination of torque and
cavitation through the counter rotating props, greatly improves the
ease of steering of a boat. Additional top speed of 3 to 4 MPH with
counter rotating props can be expected. The factory list price for
this is $1280.00 for two motors." This
is the first instance of a large HP twin engine counter rotating
design. It did not prove too popular, mainly due to the high initial
cost. A Mercury Mark 78 could be purchased in 1958 for $950. The
counter rotation idea faded from view with the demise of Oliver in
1960, only to become popular again many years later with the advent of
high horsepower outboards. To make a motor counter rotating, Oliver
made a simple modification to the shift linkage bell crank in the
exhaust housing, and changed the prop. The forward gear would become
the reverse gear, and the reverse would become the forward. Oliver
sold a kit for the do-it-yourselfer to change his motor to counter
rotating. Oliver was traveling in uncharted water though. In June of
1958, Oliver issued a service bulletin to correct previous
instructions. It instructed you to install the right hand rotation
engine on the starboard side of the boat, and the left hand engine on
the port side. Trial and error.... This month we will list the numbers for Martin outboard motors. Model HP starting serial number 1946 60 7.2 25000 1947 40 4.5 15000 60 7.2 25000 1948 20 2.3 5000 40 4.5 15000 60 7.2 25000 1949 20 2.3 5000 40 4.5 15000 60 7.2 25000 1950 20 2.3 5000 40 4.5 15000 60 7.2 25000 66 7.2 25000 Hi-Speed 60 7.2 25000 100 10 55000 1951 20 2.3 5000 45 Synchro-twist 4.5 15000 75 Synchro-twist 7.5 25000 75 Twist Shift 7.5 25000 Hi-Speed 60 7.5 25000 Hi-Speed 100 10 55000 Standard 100 10 55000 1952 45 4.5 Synchro-twist 75 Aquamatic 7.5 Twist Shift 100 Aquamatic 10 Twist Shift 1953 20 2.3 5000 45 4.5 Synchro-twist 75 Aquamatic 7.5 Twist Shift 100 Aquamatic 10 Twist Shift 200-EHA Silver streak 20 65000 200-EHO3 Silver Streak 20 65000 1954 20 2.3 A-15000 45 4.5 BB-58000 75 7.5 CC-117000 100 10 DB-19000 200 20 EHD-9000 200 20 EHA-9000 |
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