No start question
 

I'm helping my BIL try to start his '31 Tudor. Was running fine, then a couple days ago would crank but not start. Went out today and tested for spark against a head nut - nice strong spark. Checked for fuel flow at the carb - good flow. Set the GAV at 1/2 turn, fully retard the spark, throttle cracked, turned over strong, but no start - not even a fire. Checked for spark again to a head nut and now nothing, looked for spark at the points and nothing. Seems working the starter caused some kind of short in the ignition, where to start looking?

The ignition cable is one of the thin cable ones and the switch is a 3-position one I've not seen before.

Thanks for any assistance.

Re: No start question
 

Jump the ignition switch. An open switch would do it

Re: No start question
 

What Jackson said. Bypass the switch and check all connections in the ignition primary circuit.

Re: No start question
 

With the key on do you have voltage to the open point arm ?
If so, clean the points contact.
If not, keep checking back thru to the starter connection.
The primary plate wire is famous for chaffing and grounding to the distributor housing.
The primary lead to the distributor could be inserted too far into the housing.
The insulation on the wire inside that housing could be bad and grounding against the sheath thru the housing. That seems to happen more on the same diameter replacement cables.
A connection could be bad in the terminal box.
As mentioned, the key switch could be bad.
Make sure there is power to and thru the coil.

Re: No start question
 

Excellent systematic approach!