How different peoples experiences are. I have just completed a Clan, the latest of the 40 different engine designs built so far of a total in excess of 50 engines. The idea was to see what I could achieve with my downsized workshop of Chinese mini-lathe and mini-mill. My Clan has a slight leak from the cylinder to case joint, the holes for the cylinder screws go right through into the case and are not sealed, and the piston seal is very soft, it will not hold at all at top dead centre. Yet its first run was within a minute or so of the first fuel in the tank, it starts easily both hot or cold, and it turns the KeilKraft 5x3 prop [recommended for the original Clan] at around 10,000rpm. So much for the theories as to why your engine was initially a problem! I did make sure that the carb bore was exact to drawing, but the pointy end of the needle has a much smaller diameter than on the plan and also a much shallower taper so as not to block the carb bore too much. And by the way, I never prime the exhaust of the Clan, I just finger choke the carb a turn or two. My carb assembly was cobbled together in aluminium and the tank bowl was machined from the usual source, the toughened plastic of a cheap screw driver handle. Attached are a couple of pictures, please do not look at the con-rod of which I am thoroughly ashamed, it looke like a miniature drilled-out dog bone! Pictures do make things look worse than real life.
The first run with all the messing about finding setting can be seen here
And an even more boring video showing some hot and cold starts is here
The wobbling about is not a loose engine, it is just a vibration/frame rate artifact!
Note that in the "parts" image, the brass tube is not used as a fuel jet, the jet is drilled into the aluminium of the carb body. The brass tube is just for fuel pick up.
Ken Croft in SW France
