671 Detroit Diesels

[edbulmer]

They just don't want to start this season. The primary filters look clean. I've changed the secondary filters. Just no go. Any help or suggestions appreciated.

[Scott Berg]

make sure she's bled fully; easiest way is to use an electric fuel pump into one of the plugged ports in the engine mounted filter. Also, block heaters help....

[edbulmer]

I was told Detroits don't need to be bled. Are you sure they do?

[Scott Berg]

yes....

[hubertstephen]

only times my bros don't work is cuz the batteries suck

[glenn.225]

2 stroke Detroit's don't need to be bled at the injectors like most other diesels (they are self-bleeding to an extent) but the fuel supply system needs to be air free (check for sucking air leaks).

Most older set-ups have electrical (or gravity) and mechanical fuel pumps check to see if both are working.

In most set-ups fuel goes from tank to electric pump to primary filter to mechanical pump to secondary filter to rear of head (Left side IIRC), out front of head to crossover tube to front of other head out back of that head through a restrictive fitting (to maintain pressure) back to tank.

[Scott Berg]

exactly as Glenn notes (hence my suggestion that you can 'pressure bleed' out air by adding fuel via that engine mounted filter); had to do that to an 8-71 last week and it spun right up... just had air in the system

[edbulmer]

I can see one engine doing it but why both at the same time. Can it be sitting over the winter months in the cold?

[glenn.225]

Both engines not starting at same time??? Do they share fuel supply? contaminated fuel? Do they have a common circuit electrical fuel cut off solenoid?

Grasping at straws, not much keeps them from starting. It's not -35 degrees is it? I've had trouble starting them when it's that cold but any warmer and they usually fire right up if they're turning over fast enough. Batteries good??

[Sailmonkey]

I'd be willing to bet the injectors are above the level of the fuel in the tank. cold temps caused the seals in the fuel pump to shrink, the fuel fell back, and voila....both engines need a prime.