Bleeding fuel line in Yanmar 1GM

[blackbeard]

Today I changed the fuel filter on my Yanmar 1GM (old one was clean)and also dismantled the fuel separator (nothing inside other than clean diesel). Then I tried to bleed the fuel line using the manual lever on the lift pump.
Even after prolonged use of said lever, no fuel came through (as judged by the bleed screw on top of the filter housing), nor did turning the engine over by hand using decompressor. After many attempts I gave up, It occurred to me later that my fuel tank is fairly low down and did not have much fuel in (although not empty), so the lift pump was trying to lift air rather then fuel. So maybe if I added fuel to tank, the fuel might have some push behind it due to raised fuel level, and all would be well? does anyone have any ideas?

 

[Dellquay13]

I did my 1gm10 fuel filter at the weekend. Even starting with the filter bowl half full before reassembly, it still takes a ridiculous number of pump strokes to get fuel clear of bubbles up to the filter bleed screw. I always think it isn’t working and stop to check for leaks, but it eventually gets there. The next bleed point on the high pressure pump is a lot quicker though.

I never turn the engine over to bleed the fuel, with the raw water seacock open it could back flood the piston, with the seacock closed it could wear the impeller. I’m never organised enough to change and bleed the fuel filter half way through changing the impeller and engine anode while they are out.

 

[SaltIre]

There might be sludge in the bottom of the tank blocking the fuel out/up pipe. That was the cause of my fuel system blockage:

You can sample the bottom of the tank using one of these:

 

[pete]

It is unlikely that you don't have fuel above the pick up in the tank after just emptying the filter. Where ever possible I fill filters before I fit them both oil or diesel filters. The pump on the Yanmar works off a cam so depending where the engine stops it can restrict the pumping action.
Providing you have sealed all the joints you have disturbed correctly try turning the engine over slightly by hand while operating the pump to make sure you get the best pumping action and as said above it does take ages to fill empty filters like this. Also make sure the bleed screw is really open or removed.

 

[Halo]

Did you turn off the fuel from the tank when you started? If so did you switch it back on. ?? Obvious but it caught me out once !!
You would be better off with a full tank as less suck needed.
Agree that it takes an awful lot of pumping

 

[oldbloke]

I, and many others, put an outboard motor fuel line bulb in the fuel line, then pumping and bleeding is a matter of moments.
Also, as Pete says the priming pump only works I a certain engine position (I can't remember what it is though)

 

[ridgy]

As above, life is too short to use the engine lever.
One of these between the tank and the primary filter but ideally need someone watching when you squeeze otherwise it fills the filter very quickly and then blasts fuel everywhere.
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