Single handed fuel system bleeding - how?

Pulling fuel through the primary filter is fine, unless it needs bleeding. Then you'll pull air through.
Can hou pull the air and fuel through the primary to bleed it, I thought that you had to push?
 
considered fitting the outlet in the base of the tank, extending the fitting 10-20mm inside to create a dirt trap? gravity is pretty handy & works for free!

Thats OK provided that you have a way of getting rid of the dirt that you have trapped. Preferably a dirt sump. Otherwise some rough day, the dirt that you have trapped will spill down in to the outlet pipe.
 
What is the advantage of having the pick-up for the fuel taken through the top of the tank?

Our diesel tank outlet is on the side near the bottom, works fine and self-primes. A boatyard told us the tank installation was all wrong, that it should come out of the top, via a siphon. They said the reason for this was to stop the whole of the tank draining into the boat if there was a leak or fire.

Thinking about this later, it seemed nonsense to me, as any leak below the tank would surely continue to siphon fuel out of the tank? Similarly, I can't think why it wouldn't self-prime unless the pipe had been drained through running out of fuel.

What am I missing here?
 
Top