I've replaced everything but the mudflaps, but still no joy.

Replaced the solenoid, starter switch underneath the column, and the ignition key cylinder. Battery is new. And yet, about 70% of the time, you have to jump the S and T terminals on the solenoid to start it up.

Any ideas?

It's manual, by the way. No Neutral safety switch.

Thanks, guys.

 

I assume you have to depress the clutch pedal for the starter to work, when it does work from the key, correct? My guess is that the bushings in your clutch linkage are worn enough that the clutch safety switch doesn't get fully engaged to let the circuit get completed. I have the same problem with an 88 F-150. I replaced one bushing in mine and it helped considerably, but didn't completely solve my problem.

 

Wow. Knowing what I know about this truck, that's a very likely possibility. Thank you, masseyman. I really appreciate your taking the time to respond.