Comment And so what? (Score 5, Insightful) 333
Why not let SpaceX try and find out for themselves. They know their engines and have tested them for reuse long before they started building Grasshopper and the test protocols for Falcon 9.
The Merlins are designed to stop and start, and have done it successfully on the launch pad with the launch aborts experienced during their test flights. And SpaceX probably has a set that they've run on a static test pad for a full flight profile, then dusted them off, checked the bearings and seals and ran them again. And again. And again.
The SSMEs are excessively complex systems that have a much greater thrust than the Merlins. They need a full strip and rebuild because of their complexity.