471 Detroit Diesel Shake problem

If you have a leaking injector, it ends up putting more fuel in ONE cylinder than the others and can cause vibration (and torsional stress) regardless of being in neutral or in gear. If you put your hand on the engine, do you feel the vibration one location more than another? Is the engine smoke darker, or oil sheen visible?

Cleanslate, here's your post #9:
"I've asked them all, but will try at the commercial docks. I'm at Utsch's, for 5 years now. It's a dying / retiring breed...good DD mechanics around hear. My good one I've used is just getting to old and not wanting to do the work any more. Which I understand. He was a long time J & T mechanic in the shop dyno guy and in the field during the 70s and 80s. He knew his 71's and even was involved with my 471s , J & T so he told me called them "CAT Killers'' being my , 471s were going to put a hurting on the Caterpillar 3208s. At least that was what J & T had in mind back in early 80s.

Before him, which was only for a short time cause I only used him the past year or so, I used a not so good mechanic which I learned over time that he was not so good. I am not the best when it comes to motors( such as pulling heads, pistons etc..), but I'm slowly getting there.

Anyway, almost two years ago. Right before winter time and winterization I had the bad mechanic work on my governor , he replaced it with a new one I got from J & T.
Soon after I went to start the engine and it ran away at the dock. Vroom...up to 3000 or so Rpms before I pulled the emergency shut down knob.

Turned out to be a broken blower drive gear?..if I recall. I was never around when the bad mechanic did the work, cause I had to work ! So he replace that and all was good. I know he had the blower off and some other things in that specific area.
When he put it back together , I did not buy any gaskets for the reassembly. And I'm sure he did not. He was a big RTV user..which I'm finding out know from other work that he did.

My point is, the shake gradually started after the drive gear was replaced. Could I be sucking in or is air escaping from the blower or the blower area due to old gaskets leaking? What about connecting parts going to the blower? Would this cause a shake? Any hoses I should know about that work with the blower that could cause and air problem?

I really do not think it's my motor mounts...Original, clean not cracked Ocean Yachts paint still on the mounting base and bolts where it meets the hull engine beds. All looks good."

You'll do better down with the motors where you can put a palm on each cylinder and each motor mount to locate the source of the vibration. So bring ear muffs.

Wow- hard to imagine that many loose items. Do you think they were all left loose or became loose due to excessive vibration? I guess if this has remedied your situation they must have been loose to begin with. But, if this is the case, why wasn’t the vibration there since the work was done originally?

Thanks for sharing your update. It amazes me how often we learn something new here.

Hi every one. Just joined this forum a few mins ago. I had a vibration on one of my 671 Detroit's a while back when in neutral at the dock, and it was the front engine damper.
In my case (Viking 43 DC) the engine had to be lifted at the front to replace the damper, but did not take to long to do. You can see it wobble if that is the case.
Dennis

It is a large heavy disc on the front of the engine. It is called a crankshaft vibration damper I think. When mine went bad, it shook the whole boat at certain RPMs. When the mechanic found the problem, he had me look at it and it was going around in a kind of an elliptical orbit, rather than turning smoothly. May not be your issue, but I wanted to mention it.
All the best.
Dennis
Mod edit: link removed.

12-71ta besides vibration, what other visual inspections are recommended for general analysis. I.e. smoking after 5-10 seconds, vibration? We are buying a large hatteras and engine inspection.. Curious what others definition of “Engines running as they should”. What is considered in marine/engine as “working as they should”. Small vibration, leakage, ? Thanks and big step for us on a asis- where is vessel.. Any input is appreciated.. thanks.

It cannot be described. If you know Detroits, you know how one should start and run. Hire an engine surveyor. It's worth it's wait in gold.