67F100 with new battery starts only with battery charger

[westco]

I have a 67 F100 with a 302 out of a 85 Mustang/FMX tranny, installed 1 wire Alt. All else is stock.

Truck had been sitting since 03 when I bought it, it would at first start right off the key but now it only starts when I hook up my battery charger on the START position, i bought a new battery it checked fine but I returned it anyway, the second battery also checks out fine at 12.9v.

Could it be the solenoid for some reason it needs higher voltage?

[knightfire83]

Assuming everything else electrical on the truck is working as it should, your problem has these possibilities in order of suspicion:

- Neutral safety / backup light switch, this item completes the start circuit when you try and fire up the truck.
- Ignition switch, could have gone bad .
- Wiring from the ignition switch to the starter solenoid's "s" start terminal. Broken connection, have evidence of mice or other rodents?

Voltage isn't a likely problem, if you take a jumper wire from the battery positive post to the solenoid's "s" terminal I bet it cranks over just fine.
The battery charger isn't really upping the voltage, just supplying an alternate power source to the solenoid's coil.