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History of Johnson/Evinrude V4 Outboards
One of the
most daunting tasks a young outboard technician encounters is
sorting out all of the different models throughout the years.
Because many outboards are only used a few times each summer, they
may last for 30 years or more. Twenty year old technicians may find
themselves working on outboard motors that are ten years older than
they are! A timeline of the changes and improvements to a
manufacturer's product line can put everything into perspective for
a technician. This increased knowledge can have a tremendous effect
on a technician's self-confidence.
The history of the Johnson/Evinrude V4 product
line is very complex but can be greatly simplified
if looked at from a point of engine design changes and the year of
these changes. They can be broken down into four distinct
generations.
1958-1968 V4 Outboards
Prior to 1958 all Johnson/Evinrude engines were
either a one or two-cylinder. In 1958 the V4 was introduced.
The first V4 was rated at 50 horsepower and the
basic engine design was manufactured from 1958-1968 reaching a
pinnacle of 85 horsepower in 1968. This engine is most commonly
identified by its single 2-barrel downdraft carburetor.
In 1964 a second V4, with minor changes, was
introduced. It was manufactured from 1964-1968. This engine utilized
a single inline four barrel side draft carburetor to make 90
horsepower. For
the 1966 model year this was the first Johnson/Evinrude outboard to
produce 100 horsepower.
Externally the 1958-1959 V4 can be identified by
an square(ish) engine cover with spark plug access doors. The
1960-1968 V4 can be identified by a more rounded engine cover
without doors.
All 1958-1968 models have exhaust gases that
exit through the cavitation plate (through-the-prop exhaust wasn't
available on the V4 engines until 1969).
Other notable design changes for 1958-1968 V4
engines:
-1961 First year for battery ignition (magnetos would continue on
some models until 1967).
-1967 First year for breakerless ignition, 100 hp only.
-1968 First year for mounting the distributor under the flywheel (no
more belt driven distributors).
1969-1984 V4 Crossflow Outboards
In 1969 the Johnson/Evinrude V4 engines were
completely redesigned from top to bottom. Since 1985 (when the V4
loopcharged engines were introduced) these outboards have been
commonly called the "crossflow" V4 engines. Although manufactured
from 1969-1997 they received no significant design changes after
1984.
The 1969 V4 crossflow engines were sold in two
sizes, 85 and 115 horsepower. The pinnacle would be the 140
horsepower manufactured from 1977-1984.
There are three very distinguishing
characteristics that separate them from the 1958-1968 engines:
The first and most obvious is the modern, sharp
edged, triangular engine cover that emphasizes the low profile of
the 90 degree crossflow V4 engine (a contrast to Mercury's tall
inline six cylinder).
The second is the new one piece gearcase with
through-the-prop exhaust and rubber hub propellor (no more shear
pins for the V4).
The third is the two side-draft 2-barrel
carburetors. None of the crossflow V4 engines were ever equipped
with fuel injection, only carburetors.
Other notable design changes for 1969-1984 V4
engines:
-1969 First year for the V4 with a electric/hydraulic shift gearcase
with one mechanical cable running from the control box to the
outboard (the throttle cable).
-1973 First year for the V4 with a mechanical/hydraulic shift
gearcase with two mechanical cables running from the control box to
the outboard (throttle and shift cables).
-1973 First year for distributor-less ignition (one coil per
cylinder with timer base and sensor).
-1978 First year for the V4 with a full mechanical shift gearcase.
-1984 First year a V4 used the large V6 gearcase and large diameter
prop.
1985-1994 90 degree V4 Loopcharged Outboards
From 1985-1994 these outboards were commonly
called the V4 "loopcharged" engines. When
the compact "60 degree" V4 engine was introduced in
1995 the 1985-1994 engines were called
the "90 degree" V4 loopcharged engines. Although
manufactured from 1985-1998 they received
no significant design changes after 1995. The 90 degree V4
loopcharged engines have come in different horsepower ratings
between the 120 hp (smallest) and 140 hp (largest).
The introduction of the loopcharged V4 in 1985
brought the Johnson/Evinrude "V" engines into the modern age of
two-stroke engine technology.
A crossflow two-stroke has one transfer port
delivering the air/fuel mixture to the combustion chamber from the
crankcase. A large and heavy deflector is designed into the top of
the piston to direct the air/fuel mixture to the spark plug and to
keep it from being discharged directly out of the exhaust port.
A loopcharged two-stroke has three transfer
ports, one in the back (similar to a crossflow), and one on each
side of the cylinder. The three transfer ports direct the air/fuel
mixture to the spark plug and away from the exhaust port without the
need for a piston deflector. This is accomplished by casting the
cylinders with very precise contours in the transfer ports. The
addition of two extra transfer ports in a loopcharged engine also
feeds larger quantities of the air/fuel mixture to the combustion
chamber. This provides a dramatic increase in power over a crossflow
engine.
The main drawback to a loopcharged engine is the
cylinder size. With two extra transfer ports cast into the sides of
each of the cylinders, each cylinder is much wider. The loopcharged
V4 engine is much taller than the crossflow V4 engine. The bore
spacing on a loopcharged engine is 4.750 inches. The crossflow
engine is 4.125 inches. For identification purposes, this is also
the distance between the spark plugs.
Some other identification methods are:
-Removable transfer port covers on the crossflow engines versus
non-removable transfer port covers on the loopcharged engines.
-The exhaust port cover is removable on the crossflow and is cast
into the block on the loopcharged.
-The loopcharged V4 engines have four individual one barrel
carburetors.
-All 90 degree V4 loopcharged engines come with the large V6 type
"O" gearcase and large diameter prop.
1995-Present 60 degree V4 Outboards
In 1995 the V4 outboards were completely
redesigned. Between 1958 and 1994 all V4 Johnson/Evinrude outboards
were manufactured with a 90 degree angle between the two banks of
cylinders. Taking advantage of modern aluminum casting techniques,
Johnson/Evinrude was able to design and manufacture a very compact
60 degree V4 engine for the 1995 and newer models.
The 60 degree V4 has very few parts that will
interchange with the 90 degree V4. The biggest difference between
the 90 degree and the 60 degree is the location of the
carburetors/throttle bodies. While a traditional outboard engine
will have them mounted in front of the engine, over the crankcase,
the 60 degree V4 has them mounted on the side of the engine, over
the transfer ports.
A new small mechanical shift gearcase was
introduced on the standard length engines. The long shaft engines
use the large mechanical shift gearcase.
Four Generations of Johnson/Evinrude V4
Outboards
(Always use appropriate manual when servicing
engines)
First Generation:
When a marine technician encounters a
1958-1968 V4 outboard, common sense and a basic
understanding of a points style (magneto or battery) ignition will
get them through the ignition system. Mechanical aptitude will get a
technician through the relatively simple fuel system. The gearcases
on these models are very easy to rebuild (as long as you remember to
feed the wires through before pulling the magnets out of the
electric shift gear case).
Second Generation:
Perhaps the most common outboard ever
manufactured is the 1969-1997 V4 crossflow
Johnson/Evinrude engine. In production for 29 years these are as
basic as an outboard gets. Having the correct service manuals and a
basic understanding of breakerless ignitions and fuel systems will
get a technician through just about any problem. One special tool is
needed to rebuild the gearcase: a pinion height measuring tool. This
tool can be used on all 1969 and newer V4 and V6 outboard gearcases
and 1978-newer OMC and Cobra Sterndrive gearcases. Definitely a tool
to invest in!
Third Generation:
The 1985-1998 Loopcharged 90 degree V4
Johnson/Evinrude outboards are also very common and are serviced
almost as easily as the earlier V4 crossflow engines. As with the
crossflow engines, a service manual and a basic knowledge of
breakerless ignitions and fuel systems will get a technician through
most tasks. Rebuilding the mechanical shift gearcase is relatively
simple with a pinion height measuring tool.
Fourth Generation:
Service on the 1995-newer 60 degree V4
is a little more complicated. Having the correct service manual and
some specific Johnson/Evinrude tools is almost a requirement. These
engines
came with carburetors or DFI (Direct Fuel Injection) and attending a
factory service school is
almost a necessity for diagnosing the ignition system or fuel
system. The gearcase is a traditional mechanical shift design and
rebuilding it is relatively simple with a pinion height measuring
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