Timing John Deere A

[jlengne]

Does anyone have comprehensive information on how to correctly set the timing on a JD A. The A in question has a distributor.

 

[Anonymous-0]

We need to know what year your A is. If you have an exposed flywheel, there is one procedure. If you have a flywheel cover there is another. However, if your serial# is after 700200 it has a little window like a 60 or 620.

 

[John T]

This is just a shortened generic theoretical answer for any models:

With the plugs removed for easy cranking and the left plug wire attached to the plug but its side/threads grounded so she will fire (CAUTION Do NOT have it near the plug hole cuz fuel may exit out there) I have the point gap set correct,,,,,,,,,,,Rotate the distributor so the timing is retarded (forward CW and points closed),,,,,,,,,Get the left cylinder to TDC,,,,,,,Turn on the Ignition,,,,,,,Slowlyyyyyyy advance the distributor timing (backwards CCW) until the left plug fires (happens when points break open). That sets the static start timing while the run time advance is a function of the distributors advance mechanism and the RPM which takes a timing light to observe

If you dont wanna use the plugs firing (leave ignition OFF) put an ohm meter or continuity checker on the points (other lead to ground) and retard timing (forward CW) untill they are closed (i.e. continuity from points to ground) then with left piston at TDC slowlyyyyyyyyyy advance distributor timing (backwards CCW) until the points open (no continuity to ground). Again that sets static start timing to near TDC.

An open flywheel has the Left hand Impulse timing mark at 3 o clock in line with a flat mark on tractors side for TDC,,,,,,,The covered flywheel with a small removeable center hub has a mark on the crank lined up with the bottom (6 o clock) mark for TDC,,,,,,,The later covered flywheels with the top peep hole and cover removed have TDC and advance timing marks on the flywheel

Get it???????

John T

 

[Anonymous-0]

CAN YOU USE A 50,60 ,70 DISTRIBUTOR IN A G TO HELP OUT ON SPARK

 

[John T]

YES, Those flange mounted horizontal governor driven ignitions (lettered series and first numbered) can easily be converted from Magneto to Battery powered coil/distributor ignitions. The Delco distributor fits right where a mag did on the governors side so you need it and a coil and an ignition switch n simple wiring n get em timed right and youre off to the races.

John T

 

[Anonymous-0]

will the number dist be like a lp and move slower than a letter dist and only hit on the compression stroke

 

[John T]

Nope, the regular horizontal flange mount distributors turn at governor/crank RPM same as a mag (they mate right into the governor gears open female slot and it turns at crankshaft RPM) , I believe ??? those LP didtributors that are at right angles have a 1/2 reduction gear drive and they indeed turn at 1/2 crank speed as you noted.

John T

 

[jlengne]

Exposed flywheel.