Dashpot Adjustment - BRP Johnson J30TEL4SUA 2007 Service Manual

Dashpot Adjustment

The dashpot provides a controlled return to idle
speed when the throttle is closed. A properly func-
tioning and adjusted dashpot holds the engine
speed briefly at approximately 1500 RPM, then
slowly decelerates the engine to idle speed.
The dashpot's ability to perform a controlled return
to idle as designed should always be checked and
adjusted if necessary after synchronizing the car-
buretor throttle valves.
2
1
1. Accelerator pump lever
2. Rod
3. Dashpot unit
Start the engine and allow the engine to warm up
to normal operating temperature.
Turn the No. 3 carburetor idle adjusting screw to
set engine speed at 4000 RPM. Count the number
of turns it takes to achieve this speed from idle.
2
1. Idle adjusting screw
2. Throttle stop
IMPORTANT:
made in neutral gear.
Stop the engine. Remove the flywheel cover or
recoil starter.
Operate the throttle at the wide open position.
Then return the throttle gradually to idle speed
while watching the tip of the dashpot rod. The tip
of the rod must contact the accelerator pump lever
at the same time that the No 3 carburetor idle
adjusting screw contacts the throttle stop.
3
If these two contacts do not occur at the same
time, adjust the dashpot rod. Turning the rod
clockwise moves the rod inward. Turning the rod
counterclockwise moves the rod outward.
To reset the engine idle speed, return the No.3
carburetor idle adjusting screw to its original posi-
tion according to the number of turns that were
counted earlier.
Install the flywheel cover or recoil starter.
001345
Start the engine and, if necessary, adjust the
engine speed to the specified in-gear idle speed
of approximately 850 RPM.
As a final adjustment check, shift into forward gear
and quickly decelerate to full closed throttle from
several different throttle positions. This checks the
dashpot's ability to provide a controlled return to
idle speed each time the throttle is closed.
1
001346
MAINTENANCE
CARBURETORS
Dashpot adjustments must be
3
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