Mercruiser 4.3 ignition and Identification help

RuffleBoat

Cadet
Joined
Aug 12, 2020
Messages
7
Hello. Picked up a new to me 1998 Wellcraft Eclipse 2000s and its been very problematic thus far. I expected a few issues but as a first this has been a great learning experience lol!

Need help with identifying a few things; but here area few numbers I have been able to gather:
S-/N L011415
Block SN: GM 12552422
Thunder botl IV or V still not sure, I do have the purple/white wire but no Knock module.
I'll try to attach a picture of my timing reference tab and it looks odd. There is only one notch on it. Could this indicate a block specifically (older than 98, younger ect...) ?

Ignition question: In the picture, I setup the timing notch on the damper pulley to match the notch on the block Tab, as I understand it this should be TDC for Cyl 1 correct? If so the rotor in the distributor should point to cyl #1? but points to #4 right now (or just about).
EDIT: might have not been on the compression stroke, how do I make sure?

Current issue , cant get pass 2300 rpm under load. I have been looking, cleaning, repairing, troubleshooting things as I investigate and wait for parts to come in :)

Thanks for the help!!
 

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Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,363
TDC occurs twice, once on compression TDC and once on exaust TDC rotor must point to number 1 position ON THE CAP, NOT THE CYLINDER
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,363
firing order 1,6,5,4,3,2 so you could be on the exaust stroke pointing to #4 position
 

RuffleBoat

Cadet
Joined
Aug 12, 2020
Messages
7
Right, its pointing at the post position on the cap that connects to Cyl xxxx
just figured out that the GM s/n is for the Intake manifold ..not the block. the s/n for the block is almost impossible to see unless I remove the exhaust manifold maybe..
Heres a pic of the block tag . The flame arrestor cover has all the s/n faded to nothing :(
 

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achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
That serial number is 0L011415.

And yes, Thunderbolt 5. The V6s were never fitted with knock sensor until the EFIs and MPIs.
The timing line on the damper and the notch in the cover line up for 0 degrees (TDC). To time the engine you need either an advance timing light, like the Innova 5568, or some 'timing tape, or just measure the damper diameter and do the maths and mark a line on the damper at 10 degrees BTDC... (Diameter (in inches) x 0.087267. Mark a mark this many inches (should be about 0.7) before the line on the damper.)

Chris......
 
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