'84 Mercury Black Max - I can't find TDC

[MAtkins]

SN: 6532700

I'm through a complete rebuild, now I've got to get the timing right again.

I cannot find TDC. I tried using a chop stick and slowly spun the flywheel until the chop stick stopped.
I do notice a lull before it starts to go back down.
I tried this 4 times and by the pointer arrow, I got 3 very different results.
I'm just not getting it accurate.

SO - I thought, I can just break down and use a dial indicator.
I can set the dial indicator to 0 and then drop it back to .462 BTDC to align it with that mark

How do I set the dial indicator to 0?
If I can't find 0 with a chop stick (because the piston stops for a bit) how can I do it with a dial indicator?
There are still a few degrees of 'slop'.
Therefore, what good is the .462 mark? Obviously I'm missing something.

How can I find exact TDC so I can make sure my timing (namely the maximum spark advance) is set correctly??

 

[Chris1956]

That pause when the piston hits TDC is exactly why Merc recommends using .462 inches for the timing synchronizing. Move the piston to TDC. Measure with a ruler from top of head to top of piston (or install dial indicator and zero it). If using ruler, add .464 inches to measurement of top of piston. Now turn flywheel CCW 1/4 turn. Now turn flywheel CW until dial indicator shows .464 or ruler shows sum of your measurement plus .464. Set timing indicator on flywheel cover to .464 mark on flywheel.

 

[MAtkins]

Thanks Chris. That makes sense now (a nite's sleep helps)
I needed to realize that through the lull, the piston is sitting still at 0 which makes all the sense in the World now that I'm awake.

OK, I think I'll use a dial indicator and get this thing nailed.
Thanks again Chris..