RE: Weed wacker motors?
a sears 25cc trimmer would be a poulan 25cc, it has a decent following, the plastic back plate issue isn't much of an issue if you have some tin snips (or hack saw, or any other form of destruction to get it down to size), pretty much all the flywheels are the same size, that engine is about as good as most of them, of course the echo's are better, but they're harder to find... I have well over 20 engines in my posession and haven't paid more than $25 for any of them (and only two at that price, one 52cc and one 46cc, both on ebay, the rest were $8 or under)