anybody good with ep70 carbs? having a few issues with my car and I'm nearly sure its the carb.... put a new engine in and it was idling high around 2k revs, checked for vacuum leaks and couldn't find any so adjusted the mixture screw and it brought the revs down, started idling around 850 or so revs like it should, but it seems to drop on revs sometimes, like if i drive for a few mins and stop at traffic lights, it would sit at around 1100 revs then drop to 850 but then go a bit lower and go back up to 850 and seems to drop a rev as if it is slightly misfiring.... ignition timing was