502 carb jetting help.
05-05-2010 | 08:43 PM
#21
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Posts: 749
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From: Amesbury, ma
Timing and Idle Adjustment
Procedures For Thunderbolt
V Ignition
Setting Base Ignition Timing
1. Connect timing light to number 1 spark plug.
Connect timing light power supply leads (if
applicable) to 12 volt source.
2. Connect a shop tachometer to engine.
3. 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 run at normal idle speed. Allow
engine to reach normal operating temperature.
5. Aim timing light at timing tab, located on the tim-
ing gear cover and crankshaft torsional damper.
6. Adjust timing using the conventional method.
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.
7. Make sure that the distributor has been tight-
ened. Remove the jumper wire from the timing
terminal.
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.
3. Remove the jumper wire from the timing terminal.
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.
1. Disconnect the throttle cable from carburetor.
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.
2. Connect a shop tachometer to engine.
3. 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.
5. Adjust idle speed to recommended RPM.
6. Stop engine. Readjust cable barrel and reinstall
Procedures For Thunderbolt
V Ignition
Setting Base Ignition Timing
1. Connect timing light to number 1 spark plug.
Connect timing light power supply leads (if
applicable) to 12 volt source.
2. Connect a shop tachometer to engine.
3. 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 run at normal idle speed. Allow
engine to reach normal operating temperature.
5. Aim timing light at timing tab, located on the tim-
ing gear cover and crankshaft torsional damper.
6. Adjust timing using the conventional method.
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.
7. Make sure that the distributor has been tight-
ened. Remove the jumper wire from the timing
terminal.
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.
3. Remove the jumper wire from the timing terminal.
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.
1. Disconnect the throttle cable from carburetor.
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.
2. Connect a shop tachometer to engine.
3. 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.
5. Adjust idle speed to recommended RPM.
6. Stop engine. Readjust cable barrel and reinstall
__________________
96 HUSTLER 32, Vacuumed bagged layup, composite transom Blueprinted 502EFI's Mayfair, Dry-exhaust
96 HUSTLER 32, Vacuumed bagged layup, composite transom Blueprinted 502EFI's Mayfair, Dry-exhaust
05-05-2010 | 09:29 PM
#23
Registered
Joined: Dec 2007
Posts: 713
Likes: 4
http://www.cpperformance.com/c-161-distributors.aspx here wt i did i got a msd with the box and set mine up .idles 650 in gear and timing at 34 she runs great tops at 5600rpm i took all merc stuff off . but that me . i got one more thing for you to check the is the float level . make shore it not to high that will make you run bad at a idle !!good luck
05-05-2010 | 09:50 PM
#24
Registered
Joined: Aug 2005
Posts: 6,306
Likes: 1
From: Between A Womans Leggs in IL
Fixx
Here is the TB V info as it different than the TB IV by alot. Its always changing advance so i dont think you can check the advance at at 3500 as depending on load it will chang itself. Thats why they want you to set base timing with wire grounded at 8 degrees....The knock sensor pulls and adds advance.
I have gotten alot of great ideas and info that i need to look into all of these ideas.
See they tell u in the manual to set idle and mixture screw adjustments with the ECM in base timing mode with the wire grounded, is this rally necessary? in gear what should rpms be.
General Description
The Thunderbolt V ignition system has several spark
control features that will be described following:
D
Idle Speed Spark Control
D
Acceleration Spark Advance
D
Mean-Best-Timing Spark Advance
D
Over-Speed Control (Rev-Limiter)
D
Knock Retard Spark Control
NOTE: The Ski models do not have the Mean Best
Timing feature.
Idle Speed Spark Control
The ignition module will control ignition timing to
maintain a calibrated idle speed. This is accom-
plished by making small spark advance adjustments.
This feature is only active within a certain RPM
range. This range may be slightly different from one
engine model to another. The approximate range is
400-700 RPM.
Acceleration Spark Advance
This feature is active during acceleration only. When
accelerating, the ignition module may add more
spark advance to the “Base Spark Timing Curve”.
The amount of spark advance added, is totally de-
pendant on how fast RPM increases (how fast the
throttle is moved). This feature is also active within a
certain RPM range. This range may be slightly differ-
ent from one engine model to another. The approxi-
mate RPM range for this feature is 1200-4000 RPM.
Within this range, the module can add approximately
10 degrees of spark advance to the base spark timing
curve.
Mean-Best-Timing (MBT)
Spark Advance
During light load cruising, the ignition module
searches for the optimal ignition timing. This is also
accomplished by small changes to the spark ad-
vance. At a given RPM, the module will try to add a
small amount of advance and wait to see if there is
an RPM change. If RPM increases, it will try to in-
crease timing more. The module will continue to ad-
vance timing until it no longer gets an increase in
RPM. Conversely, if it senses an RPM drop, it will
start to retard some of the spark timing. The approxi-
mate RPM range for this feature is 1200-4000 RPM.
Within this range, the ignition module can add
approximately 10-15 degrees of spark advance to
the base spark timing curve.
NOTE: The Audio Warning System is also connected
into the ignition module circuit. If the audio warning
system becomes activated by the closing of one of
the audio warning system switches, the MBT feature
is deactivated.
Over-Speed Control
The ignition module will prevent the engine speed
from exceeding a preset limit by stopping the spark.
This feature has an RPM range that varies from mod-
el to model. The over-speed limit for a particular en-
gine is set slightly higher than the top end of the RPM
range for that model. For example, if the recom-
mended range is 4600-5000 RPM, the over-speed
limit would be set at 5100 RPM. When RPM reaches
this limit, spark is turned-off until engine RPM drops
down to a “Reset RPM”, which would be approxi-
mately 4750 RPM for this example. At this point,
spark comes back on.
Knock Retard Spark Control
The knock control feature helps provide protection
from harmful detonation. Knock control is handled by
the Knock Control Module. This module receives a
signal from a sensor that is mounted on the engine
block. The knock control module works in conjunc-
tion with the ignition module to retard the timing if
spark knock is present.
I have gotten alot of great ideas and info that i need to look into all of these ideas.
See they tell u in the manual to set idle and mixture screw adjustments with the ECM in base timing mode with the wire grounded, is this rally necessary? in gear what should rpms be.
General Description
The Thunderbolt V ignition system has several spark
control features that will be described following:
D
Idle Speed Spark Control
D
Acceleration Spark Advance
D
Mean-Best-Timing Spark Advance
D
Over-Speed Control (Rev-Limiter)
D
Knock Retard Spark Control
NOTE: The Ski models do not have the Mean Best
Timing feature.
Idle Speed Spark Control
The ignition module will control ignition timing to
maintain a calibrated idle speed. This is accom-
plished by making small spark advance adjustments.
This feature is only active within a certain RPM
range. This range may be slightly different from one
engine model to another. The approximate range is
400-700 RPM.
Acceleration Spark Advance
This feature is active during acceleration only. When
accelerating, the ignition module may add more
spark advance to the “Base Spark Timing Curve”.
The amount of spark advance added, is totally de-
pendant on how fast RPM increases (how fast the
throttle is moved). This feature is also active within a
certain RPM range. This range may be slightly differ-
ent from one engine model to another. The approxi-
mate RPM range for this feature is 1200-4000 RPM.
Within this range, the module can add approximately
10 degrees of spark advance to the base spark timing
curve.
Mean-Best-Timing (MBT)
Spark Advance
During light load cruising, the ignition module
searches for the optimal ignition timing. This is also
accomplished by small changes to the spark ad-
vance. At a given RPM, the module will try to add a
small amount of advance and wait to see if there is
an RPM change. If RPM increases, it will try to in-
crease timing more. The module will continue to ad-
vance timing until it no longer gets an increase in
RPM. Conversely, if it senses an RPM drop, it will
start to retard some of the spark timing. The approxi-
mate RPM range for this feature is 1200-4000 RPM.
Within this range, the ignition module can add
approximately 10-15 degrees of spark advance to
the base spark timing curve.
NOTE: The Audio Warning System is also connected
into the ignition module circuit. If the audio warning
system becomes activated by the closing of one of
the audio warning system switches, the MBT feature
is deactivated.
Over-Speed Control
The ignition module will prevent the engine speed
from exceeding a preset limit by stopping the spark.
This feature has an RPM range that varies from mod-
el to model. The over-speed limit for a particular en-
gine is set slightly higher than the top end of the RPM
range for that model. For example, if the recom-
mended range is 4600-5000 RPM, the over-speed
limit would be set at 5100 RPM. When RPM reaches
this limit, spark is turned-off until engine RPM drops
down to a “Reset RPM”, which would be approxi-
mately 4750 RPM for this example. At this point,
spark comes back on.
Knock Retard Spark Control
The knock control feature helps provide protection
from harmful detonation. Knock control is handled by
the Knock Control Module. This module receives a
signal from a sensor that is mounted on the engine
block. The knock control module works in conjunc-
tion with the ignition module to retard the timing if
spark knock is present.
so you installed a Holley on your boat now all that info is useless, set your timing procedure and go from their on the carburetor issues...you will need to do this by touch and feel of how the engine performs..i can go on and on about accelerator pump sizes,air bleeds,metering block modifications,accelerator pump cams,accelerator pump squatters but with out seeing it or hearing it run i would be here for hours trying to explain to you what to do.
you may want to buy a Holley tuning book and read up on your carburetor to get the feel for what your trying to accomplish
Last edited by FIXX; 05-05-2010 at 09:56 PM.
05-06-2010 | 06:25 AM
#26
Thread Starter
VIP Member
Joined: Aug 2009
Posts: 749
Likes: 17
From: Amesbury, ma
http://www.cpperformance.com/c-161-distributors.aspx here wt i did i got a msd with the box and set mine up .idles 650 in gear and timing at 34 she runs great tops at 5600rpm i took all merc stuff off . but that me . i got one more thing for you to check the is the float level . make shore it not to high that will make you run bad at a idle !!good luck
I want reliababilty and won't run the msd stuff, everyone i know on here and around be carry an extra msd box, because its not if it will fail, but when. having a single engine i cant put, put home like twins can.
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96 HUSTLER 32, Vacuumed bagged layup, composite transom Blueprinted 502EFI's Mayfair, Dry-exhaust
96 HUSTLER 32, Vacuumed bagged layup, composite transom Blueprinted 502EFI's Mayfair, Dry-exhaust
05-06-2010 | 06:37 AM
#27
Thread Starter
VIP Member
Joined: Aug 2009
Posts: 749
Likes: 17
From: Amesbury, ma
Float levels are good, just below threads and only spill out when i rock boat with caps off...Im going to spend some time this weekend and try to dial it in better and look at a few thing that you folks have mentioned, I have lots of ideas now.
The thunderbolt V system was one my boat from new and so was a AFB carb, which wasnt ecm controlled.....basicly all i did was swap blocks and new carb. everything else is same.
When i recheck timing and fuel screws, and idle should i do it all with the boat in gear?
The thunderbolt V system was one my boat from new and so was a AFB carb, which wasnt ecm controlled.....basicly all i did was swap blocks and new carb. everything else is same.
When i recheck timing and fuel screws, and idle should i do it all with the boat in gear?
__________________
96 HUSTLER 32, Vacuumed bagged layup, composite transom Blueprinted 502EFI's Mayfair, Dry-exhaust
96 HUSTLER 32, Vacuumed bagged layup, composite transom Blueprinted 502EFI's Mayfair, Dry-exhaust
05-06-2010 | 07:34 AM
#28
Registered
Joined: Dec 2007
Posts: 713
Likes: 4
ok thats good floats fine. 1990 i install a msd box and it still works good for me i have msd install in my two cars gto and camaro. ok you wt to use the old stuff . you have to do the timing at a idle . i would set it at 14 not 8 let it warm up then put it gear and adjust your carb . good luck
05-06-2010 | 08:02 AM
#29
Registered
Joined: Nov 2005
Posts: 4,554
Likes: 3
From: Fredericksburg, Va
with the flame arrester off, not running, ck to see if you a good accel pump shot when you open the throttle, you may have to change the cam position or the cam itself..also may have to up the shooter to get a better shot..Rob
