Hi,
You haven't said if you have a magneto, which a 1949 Cub would have come with, or a Battery Ignition unit, which came out in 1950 on Cubs. Some Cubs with magnetos were changed to Battery Ignition over the years.
The 1949 Cub owner's manual shows only a magneto. It also shows how to time a magneto to the engine.
The 1955 or newer owner's manuals show both types, and how to time them to the engine.
IH changed to the front pulley with 2 timing marks after Battery Ignition came out.
A 1949 Cub had 1 timing mark.
You don't need the 2 marks for setting the timing. Both types of ignition use the TDC mark for setting the timing.
Below is the 1949 Cub owner's manual. The experts on here recommend people read it, it has lots of info about operation, maintenance, and lubrication. There is a table of contents on page 1.
The magneto info begins on page 30. There are pics, you can see if you have a magneto.
http://farmallcub.com/rudi_cub/www.clea ... index.html
Below is the 1955 Cub owner's manual, the Battery Ignition unit info begins on page 41.
http://farmallcub.com/rudi_cub/www.clea ... index.html
For the battery ignition unit, use a timing light, and set the timing to the TDC mark when the engine is running at 500 RPM.
If the timing light is 12 volts, you can run it with a 12 volt battery, if the Cub is 6 volts, then the light is brighter than using 6 volts.
The 2nd timing mark lets you see if the Battery Ignition unit spark advance is working, the timing should gradually advance as you speed up the engine, and be about to the 2nd mark, when the engine is at full speed.
