To start with, there a couple of items to do before proceeding to timing your engine.
The following information and more specifications are found in the IT manual JD-10 for 50-60-70, paragraphs 112 and 113.
1. The points in a Delco distributor on a Deere are to be set at .022″
2. The cam that moves the points must be free on the distributor shaft for the advance to work.
3. With the flywheel stopped on with the LH piston on top dead center, the slots in the distributor drive (also magneto’s) are supposed to be horizontal. This usually means the crankshaft, camshaft, and governor drive gears are in time.
Gasoline, the static (stopped) timing mark on a 50 or 60 is 5 degrees AFTER top dead center.
All fuel, the mark is set at top dead center.
Liquid Propane, the mark is set at 5 degrees AFTER top dead center.
The marks on the flywheel can be seen through the little peep hole in the top of the flywheel cover.
Gasoline, the running timing on a 50 or 60 gasoline is 20 degrees BEFORE top dead center.
All fuel, the running timing is 25 degrees BEFORE top dead center.
LP, the running timing is 10 degrees BEFORE top dead center.
The running timing is set at full throttle so the advance weights and springs at at full travel.
The usual distributor for gasoline and all-fuel tractors is the Delco 1111558, runs same speed as crankshaft.
Spark plug wire nipples on the cap face the front of the tractor.
The top nipple on the cap is for the spark plug wire for the flywheel side (left side) spark plug.
LP distributor is 1111418, right angle drive, runs at half speed. The timing, distributor cap and nipples are different.
On a 50 gas, turn the flywheel until the left side piston is coming up on compression, then a little past, stop when 5 degrees AFTER top dead center show in the peep hole.
With the distributor loosely mounted and the rotor bug pointing at the top nipple, turn the body about 1/8 turn toward the front.
Turn the ignition key on and turn the body back until you get a spark for the left side spark plug. Tighten the distributor mounting bolts.
Check the running timing with a timing light and adjust or make corrections as necessary.