Chasing down a vibration

[Bob Noodat]

This is a typical dial gauge:

dial gauge.JPG

[Norseman]

I also have an annoying vibration, but only at idle/forward-aft gear only.
Beyond idle it goes smooth right away: It started a year after I bought the boat, (10-2017 purchase date)
Looked at everything, found nothing wrong and got used to it, until now.

Suspect the motor mounts, but not sure, never worked on motor mounts before, no idea what I am looking for, or not,
My 2 thrusted mechanics in Fort Lauderdale are gone, one retired back to the UK, the next one had a heart attack and went to heaven.
Used a Yanmar mechanic for the timing belt, valves and exhaust elbow, he was ok and knowledgeable, but his employer screwed me on the tensioner: (When I ordered it and told them to install it with the timing belt it was $180. When I paid the final bill it was $280. I protested, got attitude and whining. Paid and walked out for good, life is too short)
At any rate, I don’t have a good mechanic now, South Florida is full of crooks or rednecks with a tool box calling themselves “experts”.
How do I check my motor mounts? Crowbar and sledgehammer, or not?

[Jkraft]

Dag it was my understanding that they all shake at idle without being bumped up a hair. At least mine has always done it. But if yours just started that is odd. My vibration when getting on plane is still there and it’s getting hauled right after Labor Day to find out what the heck is actually going on with it. They are going to pull the shaft, prop, coupler, make sure everything is within spec. Put new motor mounts in and go from there. He can’t guarantee it will go away but it’s worth a shot at this point. I’m hoping for the best. Will report back when I get the result.