Timing

[Joe1964]

I have a 1957 or 58 mercury mark 10 I’m trying to get running again and I’m not sure where the marks are on the flywheel to make sure it’s in time. The only marks on the flywheel that I see is on top and they are straight across from each other are these the marks and if so what do you line them up with. I hope someone out there can point me in the right direction

 

[Texasmark]

Without any expert supervision I would set the throttle at idle, pull a spark plug and insert a yellow Wood covered pencil, eraser first. Rotate the flywheel until the pencil is pushed all the way out. At idle like my larger, later model engines, being a 2 stroke it goes bang every revolution. With the above positioning of the flywheel, then look for marks lining up. My somewhat limited experience with OB engines is that the spark occurs around 0 to 4* before TDC at idle and at WOT it occurs much earlier up to 20 or slightly more degrees BTDC. Don't know if this helps or not but I tried!

 

[Joe1964]

Without any expert supervision I would set the throttle at idle, pull a spark plug and insert a yellow Wood covered pencil, eraser first. Rotate the flywheel until the pencil is pushed all the way out. At idle like my larger, later model engines, being a 2 stroke it goes bang every revolution. With the above positioning of the flywheel, then look for marks lining up. My somewhat limited experience with OB engines is that the spark occurs around 0 to 4* before TDC at idle and at WOT it occurs much earlier up to 20 or slightly more degrees BTDC. Don't know if this helps or not but I tried!

I appreciate you giving me that advice I will try that again maybe I was missing something