Hello. Welcome to Just Answer.
I just looked up the manual, and found that your fans should have 3 speeds, as ceiling fans typically do.
This could be a problem with the pull chain switches. Or, it could be a capacitor problem.
If it does end up being a capacitor problem, I would probably just replace the fans... as finding and purchasing the proper capacitor can be as time consuming as installing a new fan.
There is one site that has a vast supply of various capacitors. You can find them here.
Their phone number is XXXXX979-553-3260.
The name of the company is Gulf Fans, and they are located in Texas.
If it's a switch problem, you can easily replace the switches yourself, usually with minimal disassembly.
Once you get the existing switches out, just make sure the wire that is on a terminal marked "L" gets landed in the correct location on the new switch.
Ideally, you should move one wire at a time from the old switch to the new.
The wire connected to "L" is the constantly hot power feed into the switch.
The other 3 wires are speed tap wires, for setting the various speeds of the fan blades.
If you want to get the exact same switches as the originals, those can be sourced from the same company that sells the capacitors.
Once you get a new 3 speed switch in hand, I will be happy to walk you through replacing the old ones.
If you want to test the operation of the 3 speed switches and/or the fans, we can do that with an Ohm meter, and by touching the switch leads to each other, after removing them from the switch.
If you touch the wire connected to "L" to each of the other wires, one at a time, you should be able to see 3 distinct speeds in the rotation of the motor, if the fan is working properly and the switch is the problem.
We can also read through the switch with a meter set to Ohms or continuity.
That is, after removing all wires from the switch.