There's no excuse for that. [:@]

All the information you need is here in this forum. Use the search function and look for engine break in. There is a decent thread on tapered bore break in by Dar. Read it.

If you had done a little homework and did some reading before you started the engine--you would have known that you NEVER run an engine without a prop. NEVER.

Stop what your doing and get some help from a guy at the local flying site or do a search here on RCU and do some reading. There's no excuse for doing what you did to that motor. Too much information and help available to go off and do something like that. Do some homework before you wreck it and cost yourself $100.

Now go tell your engine that your sorry and don't do it again.