so far the poulan has the echo beat in the weight department, I believe it was about 2lb 4oz including prop, I just acquired a 16cc echo (this one ran before I tore it apart, so that's a better start than the 18cc was), the engine was like 5lb 6oz with EVERYTHING on it including gas tank, once I stripped it down to magneto conversion specs it lost 2 pounds and was 3lb 6oz, but I hadn't removed the starter pawl off of the rear of the crank, once you remove the flywheel and coil/module and spark plug you are down to 2lb 6oz (5oz of that is the muffler), this is without a prop adapter or prop, haven't trimmed the case or made a prop adapter yet.

as for a prop adapter, I'm thinking of running this thing on gas/glow to keep the weight down, not to mention the magneto is mounted on the fan schroud, and the ignition system is bulky with the two separate parts. This engine has the straight cut output shaft with a keyway, I was going to make a short round spacer with a key slot to act as the flywheel did on the magneto and top that off with a standard simple threaded all the way through prop adapter with a prop bolt, this sounds a lot simpler than making an adapter that is held on by the nut, then the prop held on by say 4 smaller bolts. I suppose I could make a super short adapter and hold the prop on with the nut, or chuck the crank up in the lathe and tap the end to accept a bolt... I think I'll stick with the original plan...

I'll try to get some pics up tomorrow and as I make progress

the plans for this engine are to mount it up to either the .40 size US Aircore biplane I have sitting around, or get a .40 or .60 size Stick, heck, maybe put it on the tower trainer across the room...