Yeah I have been seeing a lot of snow blowers and power washers motors on craigslist. Those are normally two-stroke engines right?
There were some 2 stroke blowers, but most are just regular briggs 3.5 to 5s, or tecumsehs.
But here is my deal and the way I view things. Others will have different opinions.
You buy a used motor from some old piece of equipment. You will pay 35 to 50 bucks for it. Probably have to rebuild the carb, and buy parts to convert the throttle to work on a minibike. You will still have to drill holes or buy the adapter plate to use the motor on the doodle bug, you will still need a new clutch as your current one is metric, and you still need chain.
Ok, so basically a new predator is 99 dollars with the coupons that float around, you are only saving 50 or so dollars buying the used motor, then you still may put more than 50 in it getting it to run right. You profess you aren't the best mechanic, so it may be tough for you to get the old motor running correctly. Not saying you can't learn and there is no better learning tool than an old Tecumseh, nor a tool more frustrating.
I know your wife maybe angry(believe me I've dealt with angry wives, and none were more angry than me ex-wife) but you are leaps and bounds ahead to do it right the first time with a new motor than to try to use an old one.
Don't get me wrong here. I love old motors, I have one predator in my fleet the rest are old Tecumsehs. But for ease of use, always starts, and runs great the predator is the way to go.
Not to mention the loads of headers, intakes, carbs, fuel pumps, rods, fly wheels, pistons, heads and valve setups that can be added later to the predator. The only reason I suggested the used 97cc motor is the fact you can put that motor on and reuse all your parts.
Do what you wish, and everyone here will help you as much as we can. We all love to tinker, and we all love to share our ideas, and fixes to problems. This place is a true community and we all love to help.
If this is close to you...
http://harrisburg.craigslist.org/for/4051220863.html
This is in my area, I actually made fun of the ad because most people won't even look at there engines. But 45 dollars each, with clutches
http://akroncanton.craigslist.org/sno/4075700037.html