Base timing mode

"I am trying to put a 454 7.4

"I am trying to put a 454 7.4 litre Gen 6 L29 engine in base timing mode. According to the manual the #13 wire which is purple/wht, locks into base timing mode, Done that and it seems to make no difference. I timed to 8 degrees BTC with it in base timing mode removed jumper and it made no difference. Should I see a Difference?? Any thoughts?"

what do you mean "it made

what do you mean "it made no difference"?

did you follow the proper sequence outlined in the manual?

? Is your 454 7.4 litre Gen 6

? Is your 454 7.4 litre Gen 6 L29 engine carbed or EFI???

What year or serial number is your engine?

"454 MPI, What I mean by "

"454 MPI, What I mean by "it made no difference" When I shorted The Purple/wht wire to ground, That should have put it in base timing mode, I then set timing according to manual at 8 degrees
BTDC. Then removed wire and it was still the same
spot on timing mark, should there be a difference or should I see a deflection of a few degrees??"

"454 7.4 litre MPI Gen 6 SER#O

"454 7.4 litre MPI Gen 6 SER#OL068245, I marked everything and according to book base timing should be at 8 Degrees BTDC. I can only think of a couple senarios where this might happen, 1. The purple/wht wire is open or I have perfectly timed machine, Ha I think not!!"

"It sounds like you have the w

"It sounds like you have the wrong sevice book, Because you have a efi engine you don't ground out a purple/white wire, Thats for a carbed engine.

there is a way to put it in base timing by either using one of the tools in this link below, The cheapest way is to use the third tool/photo down in this link.
http://www.rinda.com/marine/marine.htm

And if you do not want to use a tool then you could still just jump two wires, By finding your data link connector and jumping two wires from the connector and they are A & C, And that will put it into base timing.

You will want to find service manual number 16, It's around here someplace, Look for a Boatfix link and you should find it. Hope this helps, Good luck with it."

"Boat Tech, I am looking at th

"Boat Tech, I am looking at the service manual #16
for my engine and it tells me to short #13 wire to ground. You may be right I will, check if it says efi or carbed. If it is for an efi it makes no difference, or sense. I will try the A-C with a jumper, to see if that is what I need, Thanks!!"

"Setting Base Ignition Timing

"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 engine
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 timing
gear cover and crankshaft torsional damper.
6. Adjust timing using the conventional method."

"Boat Tech, This is what I am

"Boat Tech, This is what I am reading! I can't find if for an EFI or Carbed unit.."

"ENG: 0L068245 Model number

"ENG: 0L068245 Model number 4542067LS 1998 MERCRUISER 7.4L BRAVO MPI 7.4L BRAVO MPI
DRV: 0L170441 5441600LS MERCRUISER BRAVO 3 2.00:1 Manufacture Date: 03/12/1998

I had time to look it up And you need part number (90-8613261 - SERVICE MANUAL #23) not 16 sorry about that. And in that service manual you will need to read page 1B-43.

Service Manual #23 GM Big Block 1998 - 2001
http://www.4shared.com/file/11610191...6/23covr1.html

And if the link above does not work then you can open this one and go to number 9 and open it up and you should find what you need there.
http://forums.iboats.com/showthread.php?t=342393

Yes you have a efi engine and you will need to do it like i was saying above."

"1B-43
Ignition Timing
Two i

"1B-43
Ignition Timing
Two items of test equipment are required: an inductive pickup timing light and a Scan Tool.
1. Connect timing light (91-99379 or similar) to No. 1 spark plug wire. Connect power
supply leads, if applicable, on light to 12 volt battery. Refer to Specifications - “Engine
Rotation and Firing Order,” for cylinder numbering and location.
2. Connect a shop tachometer to engine.
NOTE: Before starting engine make sure the timing tab and mark, or marks, on crankshaft
damper are clean. Chalk or white paint on timing marks may help visibility.
NOTE: With engine running, set the scan tool or Marine Diagnostic Code Tool to the
SERVICE MODE and follow manufacturer’s instructions. On MEFI 2 and MEFI 3 models,
engine rpm will automatically increase to a higher rpm. You do not have to increase it
manually, as stated in the following steps.
3. Connect the Scan Tool to the DLC connector (in the electrical box or on the electrical
bracket) of the wiring harness.
74228
a - Timing Tool
4. Start the engine. Allow it to reach normal operating temperature.
5. On MEFI 1 Models: Manually adjust the engine throttle to 1800 rpm.
6. Aim timing light at timing tab, located on the timing gear cover and crankshaft torsional
damper. Check the timing. Refer to “Specifications.”
72328
7. Loosen the distributor clamp bolt enough to just be able to rotate the distributor with
some resistance.
8. Aim timing light at timing tab and recheck location of timing mark. Slowly rotate the
distributor clockwise or counterclockwise to adjust the timing to specified degrees.
9. Aim timing light at timing tab and recheck location of timing mark. Repeat Step 8 until
timing is correct. Torque distributor hold down bolt to 30 lb-ft (40 Nm).
MAINTENANCE SERVICE MANUAL NUMBER 23
Page 1B-44 90-861326--1 MARCH 1999
10. Manually close the throttle to bring engine rpm back to idle.
IMPORTANT: Set the tool to NORMAL MODE before attempting to resume normal operations.
If the setting of the tool remains in SERVICE MODE, the ignition system will
operate only in the “Service Mode.” This means that the additional timing advance
features would not function.
11. Set the Scan Tool to NORMAL MODE. Disconnect the tool.
12. Stop the engine. Turn ignition key to OFF position.
13. Remove timing light."

"paul_rodgers, Here is an up d

"paul_rodgers, Here is an up date about using a jumper wire to jump the data link connector, Do not jump A & C that is incorrect information, You need to jump A & B at the DLC connector.
You can jump the A & B terminals with a paperclip. Just make sure it doesn't touch any metal on the engine and ground out.

See the photo of the DLC connector (Number 3) near the bottom of this link, You will see how close the wires are to each other on the jumper tool. And that is A & B, Not C.
http://www.perfprotech.com/store/articles/mercruiser-engine-timing.aspx

Sorry if this causes any inconvenience to you."

"Boat Tech, not an inconvenien

"Boat Tech, not an inconvenience at all, I Flew home to South Carolina, Boat is in Mobile Bay Al.
I am trying to get all info that I will need to get this thing timed, I am close but not right on yet. I don't have a scan tool so the paperclip will have to work. I don't mind buying a scan tool but to use it only once doesn't quite make good sense as I only work on my boat.
Thanks for all the help with this."

Do I need the scan tool or can

Do I need the scan tool or can I just short wires A&B on the DLC to get to base timing mode?