Jon i have seen that baby picture before and i could not help notice that tiller. I have always liked antique items and have a few things of such, clocks , lionel, etc,etc. I have a troy tiller about 18 seasons old i always use.
That tiller looks very similar perhaps  not exact model but perhaps the maker
Graham Paige and Frazier "Rototiller" 1946-1952    Model B1-6
The tank and mount its on along with front grill , radiator hose and such look exact to the one your baby picture displays. Its about 3/4 down on left side.
Here is link

http://rototiller4.homestead.com/rototiller.html

:-)

Martin,

I don't remember the brand, etc. I did look a lot like the one you pointed out. All I remember was that it was yellow, and it was a big beast; much, much  bigger than the rototillers you see today, such as my Troybilt. It had to be close to 6-7' from nose to handle tip. My father sold it to some people who moved to Oregon in the early 70s to "homestead" in the hills. Don't know where it went from there - might still be there somewhere.