If you have not opened up the engine it is unlikely that it is out of timing. If the mixture is very rich, it may take a glow plug driver to keep the glow plug lit. Before I would go tearing the engine down, I would replace the glow plug with an OS Type F plug. Read the notes at the top of the engine thread about Saito's and go to
http://saitoengines.info for further information.
Remember your engine has not been run in a very long time. It make take a few runs to loosen it up. I am thinking the high speed needle ought to be about two turns to start with. If you are using more turns then it is very rich and the excess oil will cool off the glow plug, ergo keep the driver installed until you lean out the HSN. The factory setting for idle is the low speed needle is flush with the throttle arm (which is also rich), it is leaned out but small turns inward (maybe an 1/8 of a turn at a time).