Launching Remote Kernels takes a lot of time

Question

I recently played around with establishing a remote kernel setup without using mathematica grid. To do this I use the LaunchKernels[] command and ssh to establish the connection. A call to my remote desktop (RemoteDesktop) then looks like:

Needs["SubKernels`LocalKernels`"]
LaunchKernels[RemoteMachine["RemoteDesktop", 
  "ssh -x -f -l username `1` math -mathlink -linkmode Connect `4` -linkname `2` -subkernel -noinit >& /dev/null &", 8]]

Which returns the following error:

SubKernelsProtectedkernelFlush::time: Operation LinkWrite timed out after 15.` seconds

It actually took me some time to figure out, that launching a kernel on RemoteDesktop actually takes longer than the predefined limit of 15 seconds. If I increase the limit to some way higher timespan like this:

Parallel`Settings`$MathLinkTimeout = 100.

LaunchKernels[] sure takes its time, but all the kernels are launched eventually.

So I cannot help but wonder: Is this an ordinary behavior or do you think something is going wrong regarding my setup, which results in launching kernels taking more time? If so, what could be the reason?

Further information: I am working on a MacBook Pro with OS X 10.9 and Mathematica 9.0.1. I testet remote connections to another Mac with OS X 10.8 and Mathematica 9.0.1 and a 64 Bit Linux Machine. Launching kernels took way longer than 15 seconds in each of these two scenarios.