Inline fuel pump - tank end or engine end?

demonboy

demonboy

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Been having an interesting discussion on where to place a 12v inline fuel pump. Some argue that it should be by the tank so that it can push the fuel through easily, but the counter argument is that any crap would then be pushed through the filters. The argument for a pump at the engine end is that any fuel at this point will be filtered, but the flip side is that it if the filters block the pump could run dry, and it's effectively pulling the fuel rather than pushing it, which isn't good for the pump.

Currently I have, in order from the tank, a centrifugal filter, a Racor water-separator and then a small engine-mounted fuel filter. The distance from the tank to the centrifugal filter is approx. 3-4m.

Is there a general consensus on where to put it? Is there an argument for putting a filter immediately after the tank and before the pump? I have a whole box of spare fuel filters (the long type with the plastic tap at the bottom) that no longer fit my new engine (Beta 60). Maybe I could mount one of these after the tank and before the pump?
 
Your choice old boy but do remember that you must select the pump, some have short suck long blow, long suck short blow, some will pull a head and others not designed to suck. A reasonably priced Facet pump sometimes has an internal filter according to model.
 
Hi mate.
Depends on the type of pump. If it's a Facet cube (which are common, if not perhaps in your neck of the woods), the manufacturer's instructions are very clear that it's much better pushing than pulling and should be placed close to the tank and low down. It should also have a (fairly course: 74 micron) filter before it.
Don't the instructions tell you?
 
macd said:
Don't the instructions tell you?
Click to expand...

Hi Mac,

I haven't bought one yet, I'm just doing some pre-purchase research. Looks like both you and third engines have mentioned Facet, so I'll have a look into them. Five day holiday coming up here in Thailand, so progress will be Thai-style on this little project ;)
 
demonboy said:
Been having an interesting discussion on where to place a 12v inline fuel pump. Some argue that it should be by the tank so that it can push the fuel through easily, but the counter argument is that any crap would then be pushed through the filters. The argument for a pump at the engine end is that any fuel at this point will be filtered, but the flip side is that it if the filters block the pump could run dry, and it's effectively pulling the fuel rather than pushing it, which isn't good for the pump.

Currently I have, in order from the tank, a centrifugal filter, a Racor water-separator and then a small engine-mounted fuel filter. The distance from the tank to the centrifugal filter is approx. 3-4m.

Is there a general consensus on where to put it? Is there an argument for putting a filter immediately after the tank and before the pump? I have a whole box of spare fuel filters (the long type with the plastic tap at the bottom) that no longer fit my new engine (Beta 60). Maybe I could mount one of these after the tank and before the pump?
Click to expand...
does the pump push or pull, no point in at the delivery end & you cant prime it
 
The Facet website gives full details of all the pump models; p.s.i, how far they can lift, whether they have check valves and/or positive shut-off etc.

I've just fitted one an opted to fit it between the course CAV filter and the engine-mounted fine filter, i.e. it sucks through the coarse filter and blows through the fine filter and is about 250mm above the bottom of the tank. All working fine thus far and it's made bleeding so much easier.
I went for the 60300 which gives 2-4p.s.i, 12" dry lift and 50" wet lift for my 60hp engine;
 
demonboy said:
Hi Mac,

I haven't bought one yet, I'm just doing some pre-purchase research. Looks like both you and third engines have mentioned Facet, so I'll have a look into them.
Click to expand...

Having grown up mainly with carburetted motorcycles, I don't really know one pump from another, but Facet seems to have an excellent reputation. Mine (I can quote the model if you need it) seems to fail safe -- i.e. it will allow fuel flow even if it stops working. So, unless the tank level is particularly low, the mechanical lift pump will take over. (At least, that's my understanding.)

It's also a major boon if you get cruddy fuel, as happened to me last year. A leccy pump makes it relatively easy to contrive a fuel-polishing set-up in situ. Of course a proper tank drain would be even better, but that's for another winter.
 
macd said:
I don't think anyone's talking about the OP throwing his pimary filter(s) away, just ensuring there's a filter upstream of the leccy pump.
Click to expand...

I am saying that his engines primary filter will often have requirements for where it is placed relative to the pump. The primary filter is the important one because the engine is far more important that the pump. And, in any case, my understanding is that many filters prefer to be on the vacuum side which protects the pump also. So, you choose the appropriate pump for the filter and engine not the appropriate filter for the pump and disregard the most important things in the setup.
 
A primary filter that needed to be downstream of the first pump would be absolutely no use in 99% of yacht fuel systems.
It's there to catch water and crud which must always be allowed for in diesel systems and you don't want that going through most pumps, although some transfer pumps would cope.
There should be an engine filter after the pumps. They occasionally trap bits of rubber that fall off pump valves etc!
 
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