Detroit 6V92 fuel leak

O K, enough of our guessing. After replacing the Racor top gasket and O ring, Lets get some vacuum gauges in there.
#1, on top of the Racor.
Run the main, close the supply valve, draw a low pressure, shut down and close the return and see what happens.
It's going to take some real trouble shooting with gauges if resealing the Racor tops do not work.

I was just in Grand Rivers on a Cat issue. Wish I'd known about this a month ago.

+1 , Great idea Ralph.

I've had this issue with those smaller coffee can looking fuel priming pumps. They have small plastic anti syphon valves in them that go bad and this has caused a fuel priming loss on a few Detroit Diesel boats I've run over the years.

Do all DD have a fuel pump on them? Always wondered how they get their fuel. I just know they do...Lol.

I do know on my boat it's gravity fed to the Racors, them after that IDK.

The priming pumps I'm talking about were electric and an add on.

Yes all detroits have a fuel pump (mechanical usually).

There is a thought; It's a gear driven fuel pump in front of the blower.
A lil lip shaft seal keeps the fuel in. There is a weep hole behind this seal.
It's hard to reach or see under there, the governor to port and usually the shut down solenoid above make this fuel pump out of sight / out of mind. Can you get a finger under the pump and feel fuel? Wont be a bunch, just moist is all needed to know.

Still need pressure gauges installed to diagnose this better.

Another question; do you have block heaters?

Another question: do you smell raw fuel ?

In the exhaust when starting or in the sump oil?

or just in the bilge area when you lift the hatch ?
Not so much bilge water, if any, just whiffing fuel smell in the air ?