Ford 851D fuel leak

[Cattleguard]

On the right side of the 851 diesel valve cover there is a round cover held on by a wing nut. Last time I started it diesel started spraying out of valve cover around that disk.
Should I suspect a leak in the tee or the excess fuel return line? Once I take the valve cover off how can I test to see the point of the leak?
Crankcase is full of diesel, but only to full line.
Also, on replacement cover gaskets should I use gasket cement?
Thank you for any help!

 

[Soundguy]

gasket cement makes gaskets that much harder to change.

when you say disc with wing nut are you refering to the breather cover?

 

[Cattleguard]

gasket cement makes gaskets that much harder to change.

when you say disc with wing nut are you refering to the breather cover?

Yes, the breather cover. When I start the engine, diesel starts spraying out from that vent. Should I suspect a leak in the feed lines to injectors or the excess return line? If the leak is not obvious right away can I start the engine briefly with the valve cover off to see what's going on?

Thanks for your reply

 

[Soundguy]

The flow of fuel in the injector feed lines is minimal. I'd deffinately be pulling the cover for a look, the return line is a common issue, sometimes the standpioe in the tank breaks too

 

[Cattleguard]

I can't find anything in my books about the standpipe. Is that in the tank directly above the fuel shutoff valve? If it is intact should I be able to feel it with a stick, going in thru the tank fuel fill hole?

 

[Cattleguard]

I believe I got the standpipe figured out. It must be inside the tank on the fuel return line. Would the standpipe be on the return line fitting that screws into the tank? If so, I might just drain the tank and take the return line off the tank and check the standpipe. Would that work?

 

[Soundguy]

Standpipe is for the return fuel, and it can break!