How do I bleed my filter?

[Kelkara]

I've just changed my external fuel filters for the first time ... and I don't know how to refill them with fuel and bleed the air out!


The engine's manual says "bleed primary filter as per manufacturer's instructions", and the leaflet for the filter system just says "bleed the air out" without explanation.


I've tried pumping the manual bleed pump on the engine with the bleed screw both open and closed, but no fuel is coming into the glass bowl ... nothing, not even a dribble.


There's no other manual pump in the system that I can see ... it seems impossible to fill the filter and bowl with fuel before installing them.


The only thing I can think of is to remove the bleed screw and siphon fuel in there using a straw ... surely this can't be right?


any better ideas?

[sveinung]

With the bleed screw open on the filter you're probably just sucking air from it when pumping, when closed you're probably not moving air past the pump so fuel will come after.
After too many times pumping like a maniac to pull fuel through lines and filter to fill the secondary fuel filter I added one of those bladders before the primary filter (same as on dinghy engines), two or three pumps and diesel is spilling out.

Try to keep the secondary filter's bleed valve open, your primary's closed, pump the engines manual pump like crazy and eventually the primary filter will fill. When you have some diesel there you can open the bleed valve there and get the air out. You'll be pumping air for a while and if you have leaks you might not be able to pull diesel from your tank into the filter at all.

You can also use a suitable syringe or your mouth to suck diesel into the filter. There's also oil sump pumps that fit pretty well to some fuel lines.

[Kelkara]

Originally Posted by sveinung

Try to keep the secondary filter's bleed valve open, your primary's closed, pump the engines manual pump like crazy and eventually the primary filter will fill.

This is the bit I was missing ... pumping like crazy ... lots and lots of pumping ... I guess it really is a very small pump.


Thanks for your excellent reply ... problem solved.

[Diesel Bill]

If the manual priming lever on the lift pump isn't pumping fuel while your "pumping like crazy" then there's a good chance the pump cam is holding on the high side of the cam so it won't stroke. Try turning the engine a bit then try priming again. On my Perkins it sometimes takes a few tries to find the sweet spot.

[mike d.]

What Diesel Bill said !

[sailorchic34]

A Lazy sailorchic installed a 12v fuel pump ($30-$50) upstream of her external fuel filter. It's a pass thru type so the mechanical pump can pull right through it normally. Really makes life easy when changing filters.

[Thumbs Up]

I just pull off my tank vent tube connection and blow into it, then put a stopper to keep some pressure in the tank. Then open the bleed screws until fuel comes out.

[stormalong]

A fuel primer bulb will pump far more diesel than the on engine fuel pump and is much easier to use. Just put it in line before the first filter.

I know many people here will criticize this method as unsafe so I will post this first. Yes, I know the criticism but I have been using this method for over a decade with no issues. Others have even said that there are diesel rated primer bulbs but I am using a gas bulb and it works great. Since this is at the high point of my fuel system even if it were to spring a leak no siphon will occur and only a few ounces of diesel could possibly leak out. Most fuel would just drain back into the tank. I have never had a leak.

It is also mounted solidly on both ends to the bulkhead so there is no bouncing around from vibration.

[Sojourner]

Based on the OP's post, this might be helpful as well: Depending on the specs of your engine, if it's like mine, you're only halfway there to restarting her tho..... After you get the filter full, pump some more, then you crack open the injector nuts, crank engine till fuel squirts out, tighten back up. THEN she'll fire up

[olaf hart]

They look like CAV filters, and have a second inlet port. You can put taps on the ports and use a hose, bulb and can of spare diesel to fill them.

Not a big fan of leaving a rubber bulb in a fuel line.

[olaf hart]

Interesting setup there, a tap on the inlet of the dual filters and none on the outlet.

Anyone else have this? Any issues?

[Pete7]

Originally Posted by olaf hart

They look like CAV filters, and have a second inlet port. You can put taps on the ports and use a hose, bulb and can of spare diesel to fill them.

Not a big fan of leaving a rubber bulb in a fuel line.

Standard fit on Peugeot diesel cars in the 1990s. Useful bit of kit for bleeding the fuel filters.

Pete

[a64pilot]

Re primer bulbs
Go here, scroll down to nasty diesel leak.
The issue to me is you should not not have fuel components inside of the boat, not rated for that, that includes auto parts store fuel hose, even though it works fine in an automobile, there are considerations like fire resistance etc. that they can’t meet.
https://marinehowto.com/hall-of-fail/