!GM10 water separator filter

[barryg]

Have just changed engine diesel filter and volvo type water seperator filter, on bleeding all ok at engine filter clear fuel, but at water seperator fuel comes out of drain on bottom but I cannot get any out of the bleed screw on top. Have checked assembly large rubber rings seated ok o ring to top of filter ok
small o ring on bolt does that go outside under bolt head have pumped long and hard! any comments would be welcome

 

[steve28]

I have seen this happen a few times, every time we allowed the fuel to filter into the bowl overnight, then try a quick bleed. If nothing still comes out, start the engine whilst still moored. Allow it to run for 10-15 mins and recheck, by this time the fuel pump will have drawn in a good amount of fuel and the bowl and filter should be ok.

 

[lw395]

The reason fuel isn't coming out is probably the pressure at this point is below atmospheric, i.e. the bleed screw is above the level of fuel in the tank. So when you undo the bleed screw, air goes in instead of fuel/airbubbles coming out.
The cure is to either fill the tank, or gently pressurise it with e.g. dinghy pump via the breather, to force the air out of the breather.
Take care it can get messy!
Hope that makes sense?