Can understand your frustration..Two starters and same problem points to ign switch or wiring! Check Voltage at solenoid terminal (with switch turned to start. Blade terminal next to battery lead) Should be a good 12 Volts. If its not , check wiring back up to Ign switch' Does it start if you bridge the terminals with a big screwdriver?
Why is it That the light at the end of a tunnel is more often than not, An oncoming train!