FINAL IDLE SPEED AND MIXTURE
4. With boat in open water, place remote control in
forward gear, idle position.
IMPORTANT: Boat MUST BE in the water and en-
gine at normal operating temperature to accu-
rately check and adjust idle speed and mixture.
5. Disconnect throttle cable barrel from anchor
stud. BE SURE NOT TO LOSE SPACER ON AN-
CHOR STUD.
Carburetor should be set so that engine idles as
smoothly as possible, with boat in the water, engine
normal operating temperature and drive unit in for-
ward gear. To adjust idle speed and mixture, proceed
as follows:
6. Adjust idle speed adjustment screw to obtain
specified idle RPM. (Refer to Section 1B -
“Tune-Up Specifications” charts.)
NOTE: Idle speed must be at specified RPM or less.
Or engine will be operating on the off idle circuit. Mix-
ture screw adjustments will be ineffective if this
condition exists.
IMPORTANT: DO NOT attempt to compensate for
other engine problems (incorrect ignition timing,
faulty ignition components, low compression,
vacuum leaks, etc.) with carburetor adjustments.
This will only cover the problem, which must be
corrected if engine is to achieve maximum fuel
economy and performance.
7.
With engine running at or just below specified idle
RPM, adjust idle mixture screws as follows:
a. Turn idle mixture needle in (clockwise) until
the engine speed begins to decrease due to
LEAN mixture.
1.
Connect a shop tachometer to engine.
b. Turn same idle mixture screw outward (coun-
terclockwise)untiltheenginespeedbeginsto
decrease due to a RICH mixture.
IMPORTANT: DO NOT turn idle mixture screws
(needles) tightly into seat, as damage to needle
and/or seat may result.
c. Turn screw in to a point between these two
extremes to obtain maximum engine smooth-
ness and RPM.
2.
If a new or rebuilt carburetor has been installed,
turn each idle mixture screw until it LIGHTLY con-
tacts seat (if not already accomplished), then
back out 1-1/4 turns. This will provide a sufficient
setting to allow starting the engine.
d. Repeat procedure with other mixture screw.
e. Readjust idle speed adjusting screw, if nec-
essary, to obtain specified idle RPM.
3.
Start engine and run at 1500 RPM until engine
reaches normal operating temperature.
8.
9.
Place remote control in neutral. Turn ignition
OFF.
Accelerator pump linkage should be rechecked
at this time. Refer to Steps 3 and 4, of Adjust-
ments - “Accelerator Pump”, as previously out-
lined and verify pump is set at 7/16 in. (11mm) as
specified.
!
WARNING
DO NOT leave helm unattended while performing
idle speed and mixture adjustments, following.
BE
CAREFUL
NOT
TO
ACCIDENTALLY
ACCELERATE ENGINE WHILE PERFORMING
ADJUSTMENTS.
10.
Refer to SECTION 2. Install and adjust throttle
cable following instructions appropriate to your
power package.
Index
90-823224--2
796
WEBER 4 BARREL CARBURETOR - 5B-15
| Categories | Mercury MerCruiser Manuals |
|---|---|
| Tags | Mercury MerCruiser 454 CID, Mercury MerCruiser 502 CID |
| Model Year | 1993, 1994, 1995, 1996, 1997 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
(4 votes, average: 4.5 out of 5)
Marine readers have rated 1993 1997 Mercury-MerCruiser GM V8 454 CID 7.4L and 502 CID 8.2L Marine Engines Service Manual Number 16 4.5 out of 5.0 based on 4 product reviews. Hugely helpful service manual! Perfect. Thank you!
Manuals are all Important for Technician
This book is invaluable if you do your own repairs. Great book.
Could not find a copy until a search brought me here.
Excellent print.
Thank you