Welcome to the Fall 2005 issue of OUTBOARD NEWS, an
electronic newsletter for the outboard enthusiast. We regret that
there were no spring or summer issues, due to the time constraints that
exist in such a seasonal industry.
has recently confirmed their plans to completely exit the traditional
two-stroke outboard market. The last two-stroke was shipped on May 27,
2005. After that date, only four-stroke outboards will be available
from the factory. The line-up will include small HP motors made by
Tohatsu and mid-range motors made by Yamaha.
has been made in the lawsuit brought by Brunswick Corp against Yamaha
Motors Corp. In the suit, Mercury claimed that Yamaha has been dumping
outboard motors in the US marketplace, at artificially low prices,
hurting US manufacturers. The decision is: yes and no. The US
International Trade Commission has ruled that Yamaha has been dumping
outboards, but that Mercury has not been harmed by it. If the
Commission had ruled completely in Mercury's favor, tariffs would have
been imposed on imports, thus raising their cost. Yamaha intends to
adjust their prices to avoid the suit being refiled.
This will effectively end a collaboration between Mercury and Yamaha
that stretches back some 30 years. In recent years, Yamaha has been
supplying 4 stroke powerheads to Mercury for some mid range engines.
This will end when the contract expires in 2006.
Recreational Products has received the Clean Air Excellence Award from
the EPA. for its Evinrude E-TEC outboard engine. This is the first
time ever a marine engine manufacturer has received an award of Clean
Air Excellence by the EPA. BRP has demonstrated that with the new
E-TEC engines, carbon monoxide emissions are typically 30 to 50 percent
lower that a similar 4-stroke engine and, at idle, are lower by a
factor of 50 to 100 times.
month we began a discussion of one of the most misunderstood parts of
an outboard motor: the propeller. This month we look at what effect
the number of blades have.
theory, the most efficient propeller would be a single-blade design.
Unfortunately, it would be extremely difficult to balance. Two-blade
props were popular in the 1950's and 60's, but are seldom seen today.
Three and four blade props are currently the most popular, and the more
blades a prop has, the smoother it runs.
Also, as the number of blades increases, the propeller's resistance
through the water increases. Depending on engine set-up and boat size,
this may reduce performance. In numerous instances, however,
performance can be improved- particularly on high-performance rigs.
Four blade props tend to keep more blade area in the water while
allowing the prop to operate nearer the surface. On offshore boats,
this can reduce ventilation problems when operating in rough seas. For
sterndrives, it can also permit operators to use more positive trim for
increased speed. On outboards, it can allow higher engine-mounting
positions for reduced lower-unit drag, again resulting in better top
A four-blade prop can enhance the performance of a large cruiser, too.
Heavy boats need more blade area to carry the load. This can be
accomplished in several ways. The first is by increasing prop
diameter, but there are practical limits due to engine design. Making
the blades larger on a three-blade prop or adding more blades also
increases blade area. Larger, heavier boats that use "elephant ear"
three-blades or four or five-blade props may suffer a slight loss in
top end speed, but will correspondingly show an improvement in midrange
efficiency and acceleration. They are also likely to let the boat hold
plane at lower speeds and offer better handling around the dock.
When changing from a three to four-blade prop the rule of thumb is to drop 1 inch in pitch.
Next issue- cup, rake and pitch.
month we will discuss McCulloch outboard motors. The McCulloch story
is a fascinating story, worthy of a whole book, but the short version
begins in 1956. The Mcculloch Corporation, which was already well
known for its 2-cycle chain saws and kart engines, was looking to
diversify, and decided the booming and profitable outboard motor
business was the perfect venue. They acquired Scott-Atwater, and
jumped right into the boat motor business. Robert McCulloch, who was a
champion outboard hydroplane racer, then applied his innovation genius
to the outboards, and produced many designs that were years ahead of
their time. The company kept the Scott name alive until 1964, when the
motors began carrying the McCulloch name. Production petered out in
the late 60's with some Sears labeled McCullochs remaining until about
1971. Replacement parts remained readily available through Mcculloch
until the early 80's. When the company was sold to overseas interests
after Robert McCulloch's death, all outboard related items were
dropped. But the question remains, why did McCulloch stop producing
outboard motors? The answer is..... A BRIDGE. For more of the
McCulloch story, go to the Reference page of our website. It is too
long to print here.
135A, 335A 25
136A, 336A, 536A 40
C3JB, D3JB 60
1961, 1962, 1963 Year is designated by first two digits of serial number.
Fishing Scott 7.5
Fleet Scott 14.1
Sport Scott 27.7
Royal Scott 43.7
Flying Scott 75.2
Next issue will will list the McCulloch labeled motors starting in 1964.