5.5
Section 5
Fuel System and Governor
5
Low Idle Speed Setting
1. Start the engine and run at half throttle for 5 to 10
minutes to warm up. The engine must be warm
before doing step 2.
2. Low Idle Speed Setting: Place the throttle
control into the “idle” or “slow” position. Set the
low idle speed by turning the low idle speed
adjusting screw in or out. Check the speed using
a tachometer.
*NOTE: The actual low idle speed depends on
the application–refer to equipment
manufacturer’s recommendations. The
recommended low idle speed for basic
engines is 1500 RPM. To ensure best
results when setting the low idle fuel
needle, the low idle speed must not
exceed 1500 RPM (±75 RPM).
Low Idle Mixture Adjustment*
NOTE: Engines will have fixed idle (no adjustment
possible) or a limiter cap on the idle fuel
adjustment needle. Step 2 can only be
performed within the limits allowed by the cap.
1. Start the engine and run at half throttle for 5 to 10
minutes to warm up. The engine must be warm
before doing steps 2 and 3.
2. Low Idle Fuel Needle Setting: Place the throttle
into the “idle” or “slow” position.
Turn the low idle fuel adjustment needle out
(counterclockwise) from the preliminary setting
until engine speed decreases (rich). Note the
position of the needle.
Now turn the adjusting needle in (clockwise). The
engine speed may increase, then it will decrease
as the needle is turned in (lean). Note the position
of the needle.
Set the adjusting needle midway between the rich
and lean settings. See Figure 5-4.
Figure 5-4. Optimum Low Idle Fuel Setting.
*NOTE: If the engine is equipped with a governed idle
adjustment (See Figure 5-19), the governor
will compensate for speed changes due to the
low idle mixture adjustment. Disable the
governed idle control by backing out the
governed idle adjusting screw and setting a
fixed idle speed using the idle speed screw
on the carburetor. Make the low idle mixture
adjustment and then reset the governed idle
speed at the adjusting screw.
Lean
Rich
Adjust to Midpoint
Not For Resale
www.SmallEngineDiscount.com
To Next Page
Loading...
