First startup at about 3 PM yesterday, and 20 minutes of driving around, light mowing, checking tempretures .
Then, MELTDOWN, the radiant heat from the lower part of the burn tube softened the plastic pipe and filter to the point that it sagged down and the front wheel caught it. Mower died.
The water cooled nozzle seemed to work great, the thermal cycling was very visible, steam bubbles aiding the flow in the upper outlet. BUT the clear plastic water supply container began distorting.
So began rebuilding with thin steel tube to move plastic further from the heat. And use a metal can as a water supply.
Smiling with every 1/2 mile!