Removing the top of the carb revealed that some particulate was still finding it's way from the gas tank. Last year we talked about installing an inline, transparent gas filter near the gas tank and now was the time to do it.
Update: It looks like the inline gas filter has solved the problem. Rojo has been running like a watch the last several weeks. It will be interesting to monitor how long it takes the filter to become visibly dirty. All it takes is a quick peek under the driver's side of the undercarriage.