Need help bad 6 71 losing prime

HELP i have a set of 1980 Detroit Diesel 6-71 and have primed them both they started fine ran for about 10 min.. or so the next day will not start back up please help
what i think? is a restriction of fuel maybe
I HAVE DONE THESE THINGS
replaced fuel takes due to leaking
primed fuel lines
and did this opened bleeder at motor then took 12volt fuel pump rite at tank and pushed fuel to motor and fuel came out bleeder fine maybe i did that wrong please let me know how to do this a diff.. way,,, I can prime and then they run for a few min.. then slowly stall

Sounds like you have a leak. Not a visible pressure fuel leak but air leaking into the line when it is put in a vacuum. Put a short clear piece of hose between the fuel tank and the engine and look for air bubbles.

yes i think it is a air leak maybe i hope for much more input on these 6 71's on priming them maybe i am doing it wrong

Check for the leak.

i did not see any leaks but will go to boat and look all over everything again

Docksidemarineservices said:

Sounds like you have a leak. Not a visible pressure fuel leak but air leaking into the line when it is put in a vacuum. Put a short clear piece of hose between the fuel tank and the engine and look for air bubbles.

Click to expand...

Perform this test.

Put a short clear piece of hose between the fuel tank and the engine, as close to the engine as you can, and look for air bubbles.