This is the set of jet drill bits I use:
http://www.ebay.com.au/itm/Metric-I...AU_HardwareParts&hash=item58aa3672a9Several people have had mysterious leanness of that carburetor, so finally finding out what size jet was fitted to the version sold in Australia would be a good thing I believe.
The M120X manual does not specify float height, or how to adjust it. The Toro manual specifies the height but does not say how to adjust it. However the Toro uses the M122X, which has detail differences from the M120X, including in the carburetor. If your float is black plastic and has a plastic pivot arm, it is not adjustable. If it has a metal pivot arm attached to the black plastic float, it is adjustable but we'd have to work out what is the reference point for measurement. If you can report which type of float you have, that will be a start anyway.
The bottom line is that we can easily make your engine richer at high speed, without changing the low speed much, by enlarging the main jet. However that would only be a sensible thing to do if the jet is wrong in the first place, which is unlikely unless your engine has been interfered with. That is why I think we should see what size jet it has, as a first step.
