Timing and Idle Adjustment
Procedures For Thunderbolt
V Ignition
1. Using a jumper wire, connect the ignition system
timing lead “13” (PUR/WHT wire) to a good en-
gine ground (–). This locks the ignition module
into the “Base Timing Mode”.
2.
Adjust idle mixture following the procedure in the
appropriate engine service manual.
Setting Base Ignition Timing
3.
Remove the jumper wire from the timing terminal.
1.
Connect timing light to number 1 spark plug.
Connect timing light power supply leads (if
applicable) to 12 volt source.
Adjusting Engine Idle Speed
This procedure should be done with boat in the water,
drive unit in neutral and engine at normal operating
temperature. Refer to the Operation and Mainte-
nance Manual for the correct idle speed.
2.
3.
Connect a shop tachometer to engine.
Using a jumper wire, connect the ignition system
timing lead “13” (PUR/WHT wire) to a good en-
gine ground (–). This locks the ignition module
into the “Base Timing Mode”.
1.
Disconnect the throttle cable from carburetor.
4.
5.
6.
Start engine and run at normal idle speed. Allow
engine to reach normal operating temperature.
IMPORTANT: In order to properly set idle speed,
the ignition module MUST BE locked in the “Base
Timing Mode”. This is necessary because of the
“Idle Speed Control” feature that exists in the
ignition module. See information on the previous
pages about this feature.
Aim timing light at timing tab, located on the tim-
ing gear cover and crankshaft torsional damper.
Adjust timing using the conventional method.
2.
3.
Connect a shop tachometer to engine.
IMPORTANT: Be sure to disconnect the jumper
wire from the ignition system test terminal before
attempting to resume normal operations. If the
jumper wire is left in place, the ignition module
will operate in the “Base Timing Mode”. This
means that the additional timing advance fea-
tures would not function.
Using a jumper wire, connect the ignition system
timing lead “13” (PUR/WHT wire) to a good en-
gine ground (–). This locks the ignition module
into the “Base Timing Mode”.
4.
Start engine and allow it to reach normal operat-
ing temperature.
7.
Make sure that the distributor has been tight-
ened. Remove the jumper wire from the timing
terminal.
5.
6.
Adjust idle speed to recommended RPM.
Stop engine. Readjust cable barrel and reinstall
the throttle.
8.
Stop engine and remove timing light.
IMPORTANT: Be sure to disconnect the jumper
wire from the ignition system test terminal before
attempting to resume normal operations. If the
jumper wire is left in place, the ignition module
will operate in the “Base Timing Mode”. This
means that the additional timing advance fea-
tures would not be functioning.
Adjusting Idle Mixture
The procedure for adjusting carburetor idle mixture
canbefoundintheappropriateengineservicemanu-
al. This procedure also requires that the ignition mod-
ule be locked in the “Base Timing Mode”.
7.
Remove the jumper wire from the timing terminal.
IMPORTANT: In order to properly set idle mixture,
the ignition module MUST BE locked in the “Base
Timing Mode”. This is necessary because of the
“Idle Speed Control” feature that exists in the
ignition module. See information on the previous
pages about this feature.
Index
90-823224--2 796
IGNITION SYSTEM - 4B-19
| 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.
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