If it's a 42cc engine, it's a Quadra, US makes the 41 (although US and Quadra are same-same). One view of the side looks more like a Quadra, from the way the cylinder fins are shaped. I have a US 41, and there is a small sticker on the side of the crankcase that has the serial number, and a model number, which is 417951. The label on the box says:
Bore--1.57 in. / 39.9mm
Strike--1.28 in / 32.5mm
HP--3.0
weight--4.5lb / 2.04kg w/ std muffler
Recommended plug--Champion RCJ-7Y
Recommended prop--18-12, 20-8

It is also stamped made in USA on the engine case and flywheel.

Gas / oil mix is 32:1

I like my -41 a lot, I use a 20-6/10 prop and fly it on a 21 pound airplane (96 inch wing). It will take off in about 20 feet.

I don't know anything about the fast start thingy; the magneto has two lead connectors on it, if you connect them to a toggle switch, that is your ignition "kill"; open switch (off) is really "run", and closed switch (on) is "kill". Mine has a spring starter, and if you've got the carb wet, it usually starts in 3-5 flips.