richardsussex
Member
I have a Racor Filter Unit 500FG connected to Yanmar 4JH-DTE. Engine 1000hrs. Fuel filter changed every 150-200 hrs. No sediment or bugs present. Fuel filter is mounted higher than tank as tank is in keel of boat but it was designed that way and there's not a lot I can do except put the fuel filter in the bilge, which might not be environmentally advisable. Problem has got worse over the past year or so (boat is 6 years old).
Have read the various posts on here about air getting into fuel systems generally and into Racor filter housings in particular. My concern is that the fuel level in my Racor filter housing seems to drop progressively after a few hours running and after, say 50hrs, it is only just covering the brass intake pipe halfway down the casing. I haven't let the level go so low as to cause engine to stall.
I have tried all of the remedies suggested - checking hose connections, bleed valve, tank connections etc. There appears to be plenty of vacuum on the system, as I found out when I once left the fuel valve on the tank closed when starting - the engine filter pump plunger was pulled right down. Also, when I do undo the T-Bar at the top of the filter there is a slight hiss of air going in. If system is left with fuel tank supply valve open there is no drop in the level, even over a period of a week or two.
I have noted that one member suggested that diesel contained some air which could find its way out and cause a pocket of air (unlikely given the 250ml or so of air we are talking about). Another member suggested that the return pipe is letting air back in (again unlikely as the return pipe has a valve where it comes out from the pump, and anyway the pipe just connects to the top of the fuel tank with no downspout pipe so it must be designed not to be kept full of fuel).
Haven't got any options left now. Have double-clipped all of the hose joins. Have used heaven knows how much kitchen roll paper looking for leaks under the filter and everywhere else. An engineer told me that a "bit of air" is OK, but if only half the filter is in the fuel then only half the filter is being used, so that can't be right.
Am currently looking for replacement O-ring and the big washer for the filter unit lid which Racor can't be bothered to supply with replacement filters (unlike even the cheapest car filters), but the current ones look OK.
Clearly this is an issue as one day the engine is going to stop after a long passage (Sodde's law it will be when berthing in a crowded marina on a windy day) so any helpful suggestions very much appreciated.
Thanks in anticipation.
Have read the various posts on here about air getting into fuel systems generally and into Racor filter housings in particular. My concern is that the fuel level in my Racor filter housing seems to drop progressively after a few hours running and after, say 50hrs, it is only just covering the brass intake pipe halfway down the casing. I haven't let the level go so low as to cause engine to stall.
I have tried all of the remedies suggested - checking hose connections, bleed valve, tank connections etc. There appears to be plenty of vacuum on the system, as I found out when I once left the fuel valve on the tank closed when starting - the engine filter pump plunger was pulled right down. Also, when I do undo the T-Bar at the top of the filter there is a slight hiss of air going in. If system is left with fuel tank supply valve open there is no drop in the level, even over a period of a week or two.
I have noted that one member suggested that diesel contained some air which could find its way out and cause a pocket of air (unlikely given the 250ml or so of air we are talking about). Another member suggested that the return pipe is letting air back in (again unlikely as the return pipe has a valve where it comes out from the pump, and anyway the pipe just connects to the top of the fuel tank with no downspout pipe so it must be designed not to be kept full of fuel).
Haven't got any options left now. Have double-clipped all of the hose joins. Have used heaven knows how much kitchen roll paper looking for leaks under the filter and everywhere else. An engineer told me that a "bit of air" is OK, but if only half the filter is in the fuel then only half the filter is being used, so that can't be right.
Am currently looking for replacement O-ring and the big washer for the filter unit lid which Racor can't be bothered to supply with replacement filters (unlike even the cheapest car filters), but the current ones look OK.
Clearly this is an issue as one day the engine is going to stop after a long passage (Sodde's law it will be when berthing in a crowded marina on a windy day) so any helpful suggestions very much appreciated.
Thanks in anticipation.
