Technical Reference Manual
Dual-function single-lever controls:
Dual-function single-lever controls operate
both shift and throttle with a single lever. The
control mechanism still uses two cables (one
for shift and one for throttle), but movement of
both cables and control of shift and throttle is
achieved through just one lever.
Dual-function, single-lever controls are also
available for twin engine applications. Although
there are two levers on the control, there is still
only one lever controlling both shift and throttle
for each individual engine.
Single lever control helped make boats so much
easier to handle that it has become the most
popular control used today. Not only do single-lever controls have a very natural, instinctive
action, but shifting is very quick and they can
only be shifted at low RPM which protects the
engine/transmission's shift mechanism.
Single function controls:
On single-function controls, one lever operates
only the shift mechanism or only the throttle.
The controls themselves may have one lever
(which would control the shift or the throttle) or
two levers (one for shift and one for throttle).
Twin engine applications will commonly utilize
2, two-lever single function controls. Both levers
of one control will operate the throttles, while
the levers of the second control will operate the
Multiple station installation:
Dual or multiple station applications almost
exclusively use single-function two lever
controls. There are two basic system designs
recommended for multiple stations:
Parallel Control System: cables from each
control station run all the way to the clutch
and throttle at the engine. This configuration is
sometimes used when cable runs are relatively
short and direct.
Series Control System: cables run from
controls at the upper station to the lower station
controls. A second set of control cables runs
from the lower station to the engine. This
method is generally used for longer, more
difficult cable runs.
When to utilize a parallel series system is
dictated by the total degrees of bend in the
cables as measured by the sum of the degrees
of all bend radii. This directly affects the
efficiency of cable action. The configuration that
gives the control system the fewest degrees of
bend is the one that should be employed.
Control head mounting:
A final choice in engine control styles is the type
of mounting. Teleflex Marine offers controls for
most applications and user preferences.
Every control has its own "mechanical
advantage" factor. Mechanical advantage
means that because you are using a lever to
create motion at the other end of a control
system (move the throttle or shift mechanism
on the engine itself) it requires less effort at
the control handle than it would if you were
pushing directly on the engine's throttle or shift
mechanism. Example: if an engine required
15 pounds of force to move its shift lever and
you use a control with a mechanical advantage
of 2.77, you would divide the force by the
mechanical advantage to determine how much
effort must be exerted at the control lever
handle to create the needed 15 pounds of force.
Understanding a control's mechanical
advantage and the amount of force to be
overcome at the engine is very important when
specifying the appropriate control.
* Approximate: varies by cable efficiency and routing.