RE: tuning problems on old ST 61series x rear exh.
Ok I have made some progress. The high end is steady with no surging and I have it running a little rich. Finally seem to have gotten the low end correct. It will idle for at least 2.5 minutes. The transition is ok after it warms up.
It seems like a totally different engine after it is warm. For example when I first crank it I can not transition to WOT. After about two or three restarts it will transition to WOT. Then I let it warm up and can transition fairly well. However if I stop her for just a couple of minutes then I have to go through the whole start up process a couple of times to get it to WOT. Does this make sense?
I am not sure if it just this engine or if it is not tuned correctly. It has one of the old carbs that the instructions tell you to set the high needle and then the low needle and then for the transition/midrange you angle the spray bar. It doesn't tell you wich way to angle it. I also don't know if more angle makes it more or less rich or lean. Maybe it is supposed to be trial and error?