Update, got the manifold trimmed, carb mounted and promptly snapped the oil injection cable off the throttle while trying to re-adjust it. So swapped to pre-mix for now. Took 2 evenings of tuning but last night I got it to fire up, idle, then run down the road at a steady 40MPH, no heat seizes, revs smoother, just plain runs right for the first time since we bought it. only issue was I stuck the throttle slide wide open and had to kill it and pull over and fix it. I think I kept trying to get more out of it and cranked it a little too hard and jammed the slide. Need to check that out tonight but I think we got this thing ready for school this fall. I also realized I had stretched the fuel line a little too far so need to get some more and make a longer piece for the new carb inlet, it's of course in a totally different spot than the other one was,