Timing an A

After you mechanical time the engine then you need to fine tune the timing.

Turn the engine at about 1500rpm or where the engine is running on the main jet.

Advance the timing until the engine starts to miss.

Retard the timing until the engine stops missing then retard the rpm by additional 50rpm. Lock the distributor down at this point. Return the engine to idle rpm.

The engine is now in time accounting for worn parts and altitude. This timing method works for any gasser engine.

T_Bone

Remove the cap and see where the rotor is pointing
if it isn't at the No1 plug tower you need to pull the mag or distributor and rotate the rotor
to the No1 plug tower and reinstall. Your rotor rotates CW and your plug wires should be in this firing order. Hal

2-1
4-3 Then see if tractor will start.

You can fine tune the timing advance by ear, may not get it right the first time, but take a wrench with as you work the tractor. You'll soon get an ear for the right setting by sound. IH tractors do a good job of talking to you, and you afterall are a SOUNDMAN.

That mark is just a very fine line that runs from front to back of the flyweel, and is marker TC (or is it DC?) 1-4. It's usually obscured by rust and dirt, but you could give a look for it while you have it lined up using Hal's method.

Both of mine I had the engines out for a rebuild anyway. As part of putting them back together, I made three marks on my engine. One was a spot of paint on the flywheel mark. The other two were on the crank pulley and the timing case cover, so that they are lined up when you're at TDC. Makes it a lot easier next time, working from the top.