When looking for a used crankshaft, always check every journal for wear or scarring. Many machine shops will stamp on the crankshaft the amount if the crankshaft has ever been machined down. Usually this is listed on the first throw of the crankshaft. If its more than .010 inch, look for another crankshaft. Once you feel youve found a good one, youll still need to have it checked by the machine shop to see if its bent, cracked, or running untrue.