olchevynut,
WOW...15.5 volts. That's pretty high! With the charging system going full bore, most electrical guru's say that 14.8 is absolute max.
If you have a solenoid starter, next time the starter does its thing, hook a voltage tester to the 'S' terminal and see if the solenoid is seeing voltage when the key is turned to START. I think one of two things are happening. The key switch might be old and funky and isn't switching power to the solenoid when turned to START, or the solenoid itself is marginal and isn't pulling in when the key tells it to.
Chevrolet's are famous for this problem. Some folks carry a sawed off broom handle with them and when the solenoid refuses to pull in, they pop the hood and tap the solenoid as their buddy turns the key on.
When the solenoid slams closed, it closes a large copper contact and signals the starter to turn. If it doesn't close, the starter won't spin. The telltale 'clicking solenoid' is another audible clue. You might have someone verify the actual output of your charging system again....when you get into the 15 volt range, your battery is going to boil and its life will be shortened.
Stuart
