obviously they were not taken care of then... any engine will act the way you describe when not taken care of,
as for noisy, change the damn exhaust if you dont like it.
crappy ignition system? they use all of the same types if ignition any other manufacture uses, points via. mag, or distributor, and solid state via distributor.
hard starting? revert back to the first line of this post... with a properly adjusted carb, proper valve lash, timing, points gap, they fire right up.
i have two well used 2 cylinders an 80's TJD out of a compressor and a 50's THD off a baler, the only thing ive done to them is rings, and cut/lap the valves/seats, both are electric start, i dont even get to push the starter button in all the way before its running.
theres a reason why wisconsins were used on high/heavy use equipment back then when quality was imporant, to both manufactures and consumers...
now a wisconsin wont run/ start good if it isnt taken care of, they require maintenance.
but you can get any garbage chinese made engine now, theyre low maintance, but they dont last!