Strange...I have found that pumps that have sat with alky in them don't like it after a few weeks, but, if the test function bogs the engine, then it should spray fine immediately after. On the other hand, it may not spray a short time later. I know Julio suggests rebuilding the pump every couple of years which I suspect is a good idea because there is no material that will completely resist methanol over a long period of time.
I don't thinh the hg overhang had anything to do with this one..but, my thinking ain't always right