Get one of these http://www.sears.com/sr/javasr/product.do?BV_UseBVCookie=Yes&vertical=TOOL&pid=00947641000
The old screws/bolts on these bikes were made of playdo, and sometimes a regular screwdriver will just strip them. This thing will just beat them into submission, making want to leave the engine. And that's what its all about, having the screws/bolts realize that YOU are the master of the engine, what you says goes, and that they should obey YOU and only YOU.