Timing Mark Location 1978 OMC 140

[Bucklebutt]

I am working on a 1978 OMC 140 4 cyl. I have looked ten-ways-till-sunday and can not find where to point the timing light. I finally found a grouve on the back side of the crank shaft pully but it aligns with nothing when the #1 cyl is at TDC. I can get the motor to run pretty good, but even then my timing light shows nothing visible to time to. Help!!!! I'm stumped.

 

[hystat]

Re: Timing Mark Location OMC 140

Sounds like your timing tab rusted off, or someone changed a rusty timing cover with one sans tab.
You can make your own timing marks on any motor.
You can use a timing tool (or make one) to find #1TDC compression accurately. with the engine at #1TDC, mark a line somewhere visible across the dampener to the block or cover.
Borrow the admiral's sewing tape measure and measure the circumference of the dampener. Then divide that distance into 360 degrees, and then mark off the advance you want and make that mark further clockwise on the dampener.
White out or a paint pencil works nice.