shaft alignment technique

I have 420 that slings a little water when in gear. It does not drip when not turning. A new cutlass bearing was installed 3 years ago. I do not think the engine was aligned at that time. What is the best way to do the alignment? I have done shorter shaft lengths with no problem. The 420 shaft is pretty long from the cutlas to the connection plate with no support. Is the shaft weight a problem? Should I repack the cutlass with new packing before aligning or is it better to align to the current shaft position? Thanks for any response! Captdds

Right, one thing I did not understand is you don't take the bolts all the way out you just loosen them slide the shaft back then slide it back on until it meets. don't tighten the bolts that yet, then turn it and see if it is even all the way around. I initially thought that you had to take all the bolts out but you only loosen them. About halfway.
Yenmar recommends replacing motor mounts every three years. But there is a way to check them. There is a certain amount of clearance that should be above the rubber and below the middle part of them out. Incredibly after all these years mine was still okay, but I still intend to replace the motor mounts. There is a bit of vibration that I would like to limit
You're getting into those kinds of things you probably want to get a good reference.

Hayden, that's a good explanation of the process. Thanks! Isn't there a pictorial of changing the rubber mounts around here someplace? That sounds like a good project (another project) for me in the fall.