External fuel filter needed for Eberspacher?

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JimC

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I am preparing to fit an Eberspacher DL4 to my boat. To obtain the fuel supply I shall be putting a 'T' piece into the engine fuel supply close to where it leaves the tank and fitting this with an independent fuel cock so it can be isolated from the engine supply. My question is: is it necessary to fit a pre-filter in the fuel line to the Eberspacher? I believe most people do not and I don't want to unnecessarily add complexity or expense.
 
JimC said:
I am preparing to fit an Eberspacher DL4 to my boat. To obtain the fuel supply I shall be putting a 'T' piece into the engine fuel supply close to where it leaves the tank and fitting this with an independent fuel cock so it can be isolated from the engine supply. My question is: is it necessary to fit a pre-filter in the fuel line to the Eberspacher? I believe most people do not and I don't want to unnecessarily add complexity or expense.
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mine is an in-lint outboard type cost pennies & easy to replace
 
pvb said:
No, there's a filter in the Eberspacher fuel pump.
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Can you explain where this filter is, and how it is changed / cleaned? I installed a new D4 Airtronic last year. The suction side of the pump seemed to be missing a washer. Is this where the filter should be? If so, it must be very small.
 
NormanS said:
Can you explain where this filter is, and how it is changed / cleaned? I installed a new D4 Airtronic last year. The suction side of the pump seemed to be missing a washer. Is this where the filter should be? If so, it must be very small.
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It is small, and it's in the suction side of the pump. Part 23 in this diagram...

eberpump.jpg
 
. . and there is nothing especially fine about the mesh that is in the filter that is shown within the pump in the diagram above. It's like a small metal mesh - nothing fancy.
 
Martin_J said:
. . and there is nothing especially fine about the mesh that is in the filter that is shown within the pump in the diagram above. It's like a small metal mesh - nothing fancy.
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It's "nothing fancy" because it doesn't need to be. There aren't any fine tolerance components upstream of it.
 
and that's why I said "it's nothing fancy".. just couldn't think of the words at the time.

I guess small particles will either be burnt off in the burner, or expelled in the exhaust gases. It just saves the pump from the big particles.
 
JimC said:
I am preparing to fit an Eberspacher DL4 to my boat. To obtain the fuel supply I shall be putting a 'T' piece into the engine fuel supply close to where it leaves the tank and fitting this with an independent fuel cock so it can be isolated from the engine supply. My question is: is it necessary to fit a pre-filter in the fuel line to the Eberspacher? I believe most people do not and I don't want to unnecessarily add complexity or expense.
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You can get an inline fuel filter from Halfords for about a fiver.
In 20 years of owning boats with heaters my experience most of of the troubles I have had with them have been due to fuel problems. Since I had a external filter fitted two years ago I have no problems since.
So to answer your question, if you can be sure the fuel you buy is always spotlessly clean with no contaminants then you wont need a filter, you might think for the small cost involved its worth the small investment required.
 
pvb said:
It is small, and it's in the suction side of the pump. Part 23 in this diagram...

eberpump.jpg
Click to expand...

Thanks very much for that. I'm pretty sure it wasn't in the kit, but I may have missed it, and will have a look in the box tomorrow.
I was aboard for the last week, ashore, and good old Eber was working overtime.:)
 
Tried to fire up my D4 Eberspacher last night or the first time in several months and despite the fact that I could clearly hear the pump clicking away, it stopped after about 45 seconds and the fan stop working.
I had the same problem when I first bought the boat and this was apparently caused by a blocked filter.
This thread (which I've resurrected) seems to describe the fault I have and now that I've located the pump I should be able to locate the filter - but I can't!
The pump appears to be sealed so my question is where does the small filter go? Does it sit behind the joint as indicated?
Any help would be appreciated.


Edit;
I should also add that I'm 100% certain there isn't any other filter in the fuel line - I traced the feed and no other filter exists.
 
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JimC said:
........ To obtain the fuel supply I shall be putting a 'T' piece into the engine fuel supply close to where it leaves the tank.......
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This can be a bad idea, it is vulnerable to leaking air into the engine supply.
I would suggest a totally separate feed from the tank.
I used a plastic inline filter.
I fitted a tap (1/4 turn ball type) at the tank. This made bleeding the fuel pipe to the heater quite easy using a syringe. If there is much air in the feed, the heater can refuse to start after too many attempts.
The filter can also be made to catch any air and feed the heater with air-free diesel.
Hope that helps?
 
lw395 said:
This can be a bad idea, it is vulnerable to leaking air into the engine supply.
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Why should it leak air? I can understand that perhaps with a LARGE engine ..like on a power boat.. the heater might suffer fuel starvation. The OP has a Hunter 31. My heater is simply T'd into the engine feed after the initial filter. I checked the pump gauze for the first time (in 26 years) recently and it was absolutely clear.......as you would expect since the fuel has already gone through a much finer filter.
 
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My Eberspacher supply is downstream of the engine primary filter. This is contrary to Eberspacher's advice, which is primarily aimed at truck installations, where the far greater fuel flow can starve the heater or even cause backflow and air in the engine supply. With the far lower fuel flow to a small engine this seems not to be a problem. My Eber has been installed for 12 or 13 year now, never had a problem with it or the engine.
 
vyv_cox said:
My Eberspacher supply is downstream of the engine primary filter. This is contrary to Eberspacher's advice, which is primarily aimed at truck installations, where the far greater fuel flow can starve the heater or even cause backflow and air in the engine supply. With the far lower fuel flow to a small engine this seems not to be a problem. My Eber has been installed for 12 or 13 year now, never had a problem with it or the engine.
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I fitted a separate feed direct from the top of the tank. A pickup located a few litres above the bottom of the pickup for the engine feed. The logic being that I would rather the heater ran out of fuel than the engine. Mind you I had the tank out of the boat to fit a small sump and drain cock at the same time so it was not too much extra effort ($$$) to add the fuel pickup at the same time.
 
I do on every install always fit one of the small 10 micron cartridge filters of the type available for small plant or oil boilers and change it along with your engine ones every year, Webasto actually supply them in the marine kit now. the dosing pumps are quite small tolerance and the walls can be scored by debris small enough to pass the Ebo strainer (it is not a filter) The reasoning behind using a proper standpipe in the tank to draw fuel has nothing to do with starvation due to the motor drawing more but rather the dosing pump having to pull fuel along a large diameter tube, the optimum bore for best and continued performance is quite low at 2mm. Also you fit the standpipe to draw from a bit higher in the tank than the standard engine draw off so it is above any sediment and also can never leave you short of fuel for the motor.
 
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