Well, I installed the new grommet at the base of the water tube. Put everything back together with the new pump. Started it, no mist of water coming from the two exhaust ports in the midsection. Carb heated up. Soon it was too hot to touch so I shut it down before the gas could start boiling.
I restarted it and while it was running I removed the drain screw at the base of the head. The water that dribbled out was initially hot then it turned cool. My guess is that the hot water was draining back down from the head and out the drain. Once drained, only the cool water being pumped from the test tank came up the tube and out the drain. So the water is reaching the head, but apparently not circulating around the head and out with the exhaust. Just not enough water pressure? I'm about to throw in the towel!