The first steps to get one of these running is set up the piston timing. Set it up wrong and you will be struggling.
The first thing is make sure you have the right sized operating lever hole in the contra piston. It should be slack, not a close fit. The next bit is to set the operating arm gap, the one where the bottom of the power piston hits.
Push down on the angled operating rod until it touches the top of the cylinder head, with the piston in the full out stroke, there should be approx 0.1mm gap between the bottom of the piston and the tip of the adjusting screw. Where the rod runs thru the cylinder is one of the few places you should put some very thin oil, it has to be almost friction free. I also, using a fine needle put a minute drop on the little end and one drop where the operating rod goes thru the hole on the top of the contra piston. Nothing at all anywhere near the bore and pistons.
The flame should be on the head side of the suck in hole. I find that a twenty second burn of a gas blowtorch is required to bring the cylinder up to temperature, then a few gentle suck ins of flame to get rid of the condensate in the cylinder. When things are getting very close to running you should find that the engine will start to 'pop' out of the suck in hole. This means that the engine is up to temperature and the piston is sealing. 1 or 2 mm out on the flame position, either up/down or side to side will be enough to stop it running. I use glass fibre wick so the flame stays the same shape and doesn't alter, as would do if a cotton wick is used.
I eventually fixed my own design burners into position, so it is warm up, light wicks, turn over by hand a couple of times and away it goes.
Maybe this will help, maybe it won't, but it is worth trying just to see if it does. I spent ages finding the settings for mine. But both are exactly the same settings.
John