For legacy Evinrude E-TEC engines (i.e., not "G2" models) the electronic shift and throttle (EST) controls are the ICON EST controls. After several years of operating the top-mounting ICON EST controls on my boat, I found a few routine maintenance items, as explained below.
THROTTLE HANDLE RETAINING SCREW
The throttle handle may become slightly loose. The handle is retained by a single screw fastener on the center of the axis of rotation. The screw fastener has a hex-socket head. A 3/32-inch hex wrench (Allen wrench) is needed to tighten this fastener.
THROTTLE HANDLE FRICTION ADJUSTMENT
The throttle handle movement friction should be adjusted so that in rough seas the motion of the boat coming downward and slamming into a wave does not cause the throttle handle position to move. This can be a problem because the throttle handle will tend to move forward, increasing engine speed. In rough seas an unintended increase in engine speed can be hazardous.
The handle movement friction adjustment is located on the forward face of the top-mounting ICON throttle assembly. A large and possibly short flat-blade screwdriver will be needed. The THROTTLE FRICTION adjustment is the screw located closets to the handle. Adjusting this screw will increase or decrease the force need to move the handle through its range of motion.
THROTTLE HANDLE SHIFT FRICTION ADUSTMENT
The SHIFT FRICTION adjustment is also located on the forward face of the top-mounting ICON throttle assembly. The SHIFT FRICTION is the screw located farther away from the handle. This screw controls the force needed to move the handle from NEUTRAL to FORWARD or REVERSE.
See more information about the Evinrude ICON EST controls in the User Guide publication:
https://continuouswave.com/whaler/refer ... 954_en.pdf
A diagram on page 17 show the friction adjustments.