I recently noticed on my starboard 454 that the crank mounted raw water pump and balancer have a pretty noticeable shake while the engine is running (idle and in gear). The shaking hoses off the pump really made it noticeable as compared to my port motor.

Is this a symptom of a motor about to crap the bucket?

I'm thinking you lost a spacer somewhere....are all the components aligned and tight? Has a support bracket failed? Is a belt loose?...Maybe it's just a worn bearing? Are the balancer bolts tight?
Just some thoughts, before you spend $$ having a pro hunt it down...

All looks good from up top. I didn't have time to go thru it very much before I had to wrap it up for the winter. I will check all bolts and such in a few weeks.

Thanks for the input. I've never been down this road before.