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Bleeding Ford engines for Novices

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    Another one of the tasks I set myself for this winter was to learnt to bleed the fuel system on my engine (I know I should know how to do this)

    The instructions in both the Ford and Nauticat manual are in my view rather inadequate for those people new to having the bleed the engine. The notes are, change filters, crack open the fwd facing bleed screen, use the lift pump to get rid of the air, start engine.

    Here’s something hopefully more useful.

    This is about the filters on the engine itself, not the primary filters elsewhere in the boat but typically towards the rear of the engine compartment. On my set up, because of the near impossible task of looking in the tanks, I fitted two Racor fuel polishing units with switch over valves to replace the standard glass bowl primary filter types. I did this mainly because replacing the filters in these units is a simple matter of undoing a big nut on the top and switching the filter. I can do one independently of the other which is useful at sea.

    On the Fords there are two filters on the engine. Ideally both need to be changed at the same time. The filters used are Sabre part no 46503 (but yours may differ). Each should come with four O rings in the box. The two large are for the filter itself, for top and bottom of the main body, one for the underside of the main body, and the fourth (which is only necessary if a copper washer is not fitted) is for the bleed screw.

    1. Have a look on the engine and see what fuel filters are fitted and order up the replacements – for Ford engines SeaHorse Power near Bournemouth in the UK are good.
    2. Turn off the diesel at the main tap(s) leading to the engine.
    3. Place lots of rags under both filters. It is hard to get a tray or anything more substantial under the filter and there will be diesel in the filter that will come out – nothing you can do about it.
    4. Loosen the main screw holding the filter, this will cause the bottom retainer to part from the filter, and the filter to part from the engine housing. Diesel will drain out.
    5. Discard old filters and lever out the two o rings on the filter and the one on the underside of the main body.
    6. Replace with new filters including the O rings and reassemble.
    7. Slacken off both bleed screws and use the hand pump – conspicuous black button by the filters in my case to fill up first the aft (when diesel comes up tighten up the bled screw), then the fwd filter. Tighten the bleed screws.
    8. Now here’s the trick, pump the pump really hard until completely firm
    9. Start the engine, and it should start, if it falters pump the hand pump again hard to force diesel in.
    10. If you get nowhere then there is probably still an airleak somewhere in the system.


    Excellent information. I would be interested to see photos of location of your fuel polishing system. I did not realize the small gasket in the new filter package was for the bleed screw if copper washer was missing. We change the copper washer periodically.


    In your excellent tutorial you write “8. Now here’s the trick, pump the pump really hard until completely firm”
    Very likely you are speaking of the “low pressure feeding pump” that is sitted on the left and bottom side of the engine. See picture attached : the lever one has to manoeuver is designated “poussoir manuel pour réammorcer, peu efficace” which is French for “manual lever for bleeding, not very efficient”.
    Apart from not being efficient it should be pointed that the lever may be totaly innefficient when the camshaft that acts upon this pump is – by ure hazard – in an innapropriate position whereby the mecanism inside is resting in “pressed” position while it should be (and most of the time it is) in “rest” position. Should this happen just rotate the engine a bit using the starter engine.

    On Naîla previous owner fitted a bleeding pump that is owerwhelmingly efficient (See attached picture with the big black button to activate bleeding). Does anyone know the name and the manufacturer of this pure marvel.


    A few pictures to attach.

    1. This is the set up on the Ford Lehman Super 90 showing the two filters, the black lift pump and the two screws on each filter top, one bleed and one holding the whole thing together.

    2. Also attached as requested is a photo of the Racor fuel polishing system I put in – both work independently from either tank – we all know older Nauticat tanks are an issue

    3. a bit by the way, but inspired point (2) above – I built a DIY fuel polishing system. A long pipe (which I can swish about in the diesel tank having removed the fuel level sender unit), connects to a pump which then goes through a Racor and back in through the deck fuel filler – creates a circuit and can be used to clean the fuel. Seems to work well as my primary filters are clean. All parts are sold as a kit by ASAP marine.



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