Got a rebuilt '36 221 FH in my '38 1/2 ton. Had trouble restarting it after it warmed up. Was suggested the solenoid was bad, they were right!! It sticks but can be booted-up by pushing the button underneath. I'm changing to 12V and understand the starter can be left at 6V, what kind of solenoid should I use? Do they have any with that button? It's kind of a neat feature.

 

Jon, just go to the parts store and ask for a 12V selnoid the 6V starter will work for awhile depending on it's condition. I went to a model A swapmeet and came across a starter that looked close to the 6V unit. The seller said it was a 12V off a 352 Ford engine, for $3.00 I decided take a chance. A short time later my 6V gave up, I pulled it and took both units apart. The took the 6V armeature and slid it in the 12V housing. Then bumped it with 12V and jumper cables, it spun. So I installed it and it's been working for 4 months now. I still need to pull it back out and install new brushes soon. Make SURE your truck has a fusable link installed where the power wire to the interior leaves the selnoid. Especially with 12 volts installed, that way it will blow before the harness catches fire. If you would like a copy of a generac streetrod wiring diagram I have from an old 1973 Rod And Custom send me an e-mail with your e-mail address. If I can be of any further assistance just let me know

hope this helps
Rod