Merc 100 Hp 2+2

[boatinnjax]

I've also got a potential timing issue. The idle timing tab is gone from the throttle arm, I'm attempting to fab and bolt one on. Also the timing marks on the flywheel are almost completely gone, all I can make out are some of the numbers and a bunch of marks, it looks like this:

28 24 20 16 12 8 4
lllllllllllllllllllllllllllllllllllllllllll

I cant see any marks under the numbers or before them either. The numbers are degrees of advance right?
I assume TDC is at the end of the 4 at the beginning of the marks (left edge).