wrong timing sequence M38A1 but it starts ...???

mehdi · Post by **mehdi** » Mon May 12, 2025 3:08 am

Hi , I have a M38A1 from 1954, bought recently
all original , 24 v
since it is running rough I decided to check ignition and replace spark plug / contact ( besides carburator check )
iginition is the 24 v shielded version
i have realized that the ignition was wired wrong according to manual ( corrected version)

it should be from bottom right counter clockwise 1342 , but on mine it is 1234 ( i consider cylinder 1 to be the one forward, fan side and 4 in the back)

yes it starts and run with this wrong firing order

when i revert to what it should be no ignition at all

makes no sense for me, before i dig down further and check all positions i was curious to hear some experts comments on this - how can it start and why would the previous guy to this ? best from Denmark, Mehdi

Post by **wesk** » Mon May 12, 2025 4:45 am

The manual illustration was originally in error. I corrected it here on my site with my own illustration showing the correct alignment. Both illustrations show the correct firing order, 1-3-4-2 and correct counter-clockwise rotation of the rotor. The actual issue is where we put the wires in the cap. The old illustration shows #1 lower right and the corrected illustration shows #1 lower left.

The wrong setup actually works if the distributor was timed to the engine using that lower right position for #1.

If when you switched the wires around she wouldn't start then the distributor was timed to the engine with #1 lower right. and will only run with the wrong wire indexing.

You have two options.

1 - Return the wires to the way they were when she was running rough. Then re-adjust timing as needed to get the timing at the correct timing mark.

2 - Keep the wires in their new index positions and remove the distributor and re-time the distributor to the engine.

The problem that prompted the correction to the wire indexing was with the #1 indexed to the lower right the distributor housing often hits the block when trying to set it's advance timing correctly before it could reach the proper position.