I have a Carrier 58STA 090 with 8 colored wired and currently a Robertshaw 9200 thermostat. Just bought a Hunter 44760 thermostat and am having a hard time connecting:

Robertshaw old connection:
W White
Y Yellow
G Green
Rc Red

Carrier wires: 8

Current 44760 connection:
R Red
G Green
O Orange
W White
C Yellow

Seems incorrect to put Yellow on C but it is the only way the system would turn on.

System is on, but only fan is blowing, no AC. Please help

Try connecting the wires as follows;

Red to the Rh terminal on thermostat with a jumper going to Rc

Yellow to the Y terminal

Green to the G terminal

White to the w therminal.

Now go to the furnace or air handler, whichever you have and check the wires on the low voltage terminal board.

They should be connected as follows.

Red from thermostat to the R terminal.

White on the W terminal

Green on the G terminal

Yellow on the Y terminal.

Now you will have two wires left that run to the AC condensing unit. Connect one of them to the Com on the terminal board.
Connect the other wire from the AC to the Y terminal that already has a yellow wire on it.

This should make you AC run when the thermostat calls for cool. And heat if it calls for heat.