Grimlock,
I had major problems getting my 5 port to turn over also. Here is what we had to do:
(1) make sure starter box spins up to full speed before the flywheel touches the starter wheel. Use a 12V car battery fully charged just to make sure you can pull the max amps.... a couple of 7.2V packs may not quite do it.
(2) at least 4 -6 drops after run oil or sewing machine / gun oil down the glowplug hole and move it around so it is soaking in the gap between piston and sleeve (bore)
(3) preheat it with hairdryer, we got the case and head too hot to touch.... a good 120deg C
(4) prime with fuel (blow in the line from the pipe, until fuel reaches carb nipple,then replace it)
(5) turn it backwards so it is at BDC. Then run it on the starter box for 30 sec with no glow plug in. Stand back, oil will go everywhere
(6) preheat again.
(7) run on starter box with no glowplug again, and whilst running it and holding it dead still, have a mate slowly screw a glowplug in till it *just* touches (not tight) then he quickly sticks a glow igniter on. Then you are away!!!
You'll need to do that (a 2 person start) for idling 2 tanks, and for the next 3-5 tanks of slow running. After that, a preheat and start with glowplug in will JUST be possible (one person start up) for the next 5 or so tanks, then it should be OK with no preheat.