Assuming its only carb issues you are having with the utility you could also consider a slide type carb found on quite a few of the victa "power units" a rotomo carb will not fit as the intake diameter is much smaller, but there are larger ones to suit the series 70 engine out there. I do have one at home i can get a photo of with measurements for reference.
Finding a donor mower for me is pretty easy, theres a good tip shop about an hours drive from home that usually has a couple of full crank victa mowers for $5-10, ill usually get 4 or 5 of them in my little corolla hatchback
