Thank thee for any help or advice ....
Question 1: How does one get the float valve assembly out ?
Watch my carb videos.
Kymco Grandvista / Grand Dink:Carburetor Cleaning & Theory three part series: Question 2: Are there any after-market sources for a replacement carburetor ?
No, my videos cover this in detail too. Consider ordering parts that broke. If you stripped a screw you can take the carb to a machine shop and they can remove / re-thread the holes.
Regarding the stripped screws. Buy a hand impact driver and you will never strip a screw again. Use it first when in doubt. Don't feel bad. I too stripped the screw that you cut "slotted" with a hack saw - I used my rotozip to slot it. On the other screw I use my impact too and had no problems.
Hand Impact Tool $7 also available at any auto store fairly cheap.
http://www.harborfreight.com/impact-screwdriver-set-with-case-37530.htmlIf your carb is really clogged then it might be best to replace it even at a cost of $300. If you do replace it save the old unit and sell the parts. The vacuum diaphragm is $50 new and is the most commonly sold part so you can recover some money.