Share 'Using a tillerpilot on a Tiki 30'

We have set up a tiller pilot on our Tiki 30 which uses an extension rod connected to a universal joint connected to another rod coming off the tiller, close to the rudder, at 90degrees.  We have found it unreliable to use and suspect that the problem is the weight of the tillers being too much for the motor in the tillerpilot; has anyone else experienced this?  We have a windvane so the back up…