The crack I found in the motor mount grounded me. So I took off the engine and ordered a new mount. As I pulled the engine from the motor mount, the cracked member fell off! It wasn't cracked, it had been broken a long time. Now the fun begins as I re-hose everything, inspect everything and consider changes.
I ordered all new hose from Rotax. The spring type clamps don't work on this engine according to Rotax, so I am back to gear driven clamps. I was told the engine had 68 hours on it before I bought it. I am skeptical now. Are there any tell tale wear spots that can help identify potential age? the cracked motor mount has probably been that way for at least 250 hours, maybe the whole 450 I have flown it. I think it accounts for the bulk of my problems with carb balancing, vibration isolation and general funny behavior that could have been well … not so funny.