How to set ignition timing
What should the ignition timing be set to? I'm talking about the degrees before or after TDC. My brother has a 1910 with an added tooth wheel for an added starter. We marked TDC with white paint, then checked timing fully retarded and fully advanced. We checked it two ways, with the motor off and simply rotating the toothed wheel (attached to the crankshaft of course) until we heard the coils buz. Then we did it with the engine running and using a timing light. We got different answer for static (engine off) and dynamic (engine running). I believe that is expected. I plan to text my 1909 tomorrow for static measurements. I don't have a tooth wheel but I do know where the hand crank is when it is TDC. Then I can turn the crank until the buzzing starts and measure the angle between TDC and where the buzzing started. I couldn't find any mention of degrees or distances around the flywheel related to when the spark should happen. So any info you may have, documented or just what you've observed, would be appreciate.
My 40 hp ‘10 Chalmers is set at 15 degrees past TDC. No starter so I may be bit too retarded but I don’t want a kick back.