Fuel filter location question

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Dumpstick

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Relatively simple question: fuel filter upstream from the pump, or downstream?

Particulars:
-Relatively low horsepower application, on road. Less than 75 hp, probably less than 50.
-Carbed engine, electric fuel pump; so this is a low-pressure pump. Maybe 5-7 psi.
- pump mounted within 2 feet of tank, pushing fuel 6 feet.
- No filter or sock in tank, straight straw feed.

This is a project vehicle, about which I will make a thread later. The problem: I acquired it non-running, probably due to electrical problems (dash was in the front seat). I've sorted the majority of that, now it's time to get it running.

Do I set up the filter so the pump pulls gas through it?
Or, should the pump pull straight from the tank and push the fuel through the filter?

I've seen it both ways on various vehicles, from the factory. I have no idea how this was originally set up, and it's odd enough that detailed info is hard to find.

Opinions ?
 

swampratt

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I always have a filter right before the carburetor this will catch anything the fuel system spits out including failed fuel pump parts.
You could also stick one before the pump and it will not hurt anything and could save the pump if you get trash in the fuel tank.

I ran one before and after the pump many times.
A clean fuel filter is not a restriction in flow.

Most fuel tanks have a sock filter of some kind in them I have made fuel tanks and not used any in tank filter and I have had no issues but fuel was always clean.
 

MacFromOK

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If it's an electric fuel pump, I'd put the filter before it. Otherwise, I'd put it after.

The suction side is easier to disrupt than the pressure side, and (in my experience) chances are slim you'll get anything in the line that would affect a mechanical pump.

Just my 2¢ ... :drunk2:
___
 

Dumpstick

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I see...50/50.

Perhaps I'll run 2 filters. A larger one between the tank and pump, a smaller one after the pump.

This thing has been sitting for at least a year, probably much longer. The fuel in the tank is rotten, so I'll rig a temporary tank to get it running. I'll drop the tank to clean it out.
 

Dumpstick

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Before:
Fuel pump-Filters old.JPG


After:
Fuel pump-filter new.JPG


The (new) pump draws through the filter.
 

swampratt

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I have seen what kind of crud build up can be in an old steel fuel line some are plugged with so much crud they barely trickle any fuel out of them. All my old vehicles got new steel line installed in them and all my vehicles regardless of new or old line got a filter right before the carburetor.

I would not warranty a carburetor rebuild unless it had a filter before the carburetor.
Many carburetors have a filter built into them.

Some of those were a bit restrictive and some carburetors had a fine screen basket pushed into the back side of the seat to catch any last bit of crud that could get between the needle and seat and flood out the engine and cause poor running or a fire.

What you have done so far looks good.
 

Tanis143

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If you have an old steel tank and lines with rotten gas I would def invest in a new tank and lines. Especially if the tank wasn't sealed. Water vapor would have turned the inside to a rust stalactite landscape.
 

Dumpstick

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If you have an old steel tank and lines with rotten gas I would def invest in a new tank and lines. Especially if the tank wasn't sealed. Water vapor would have turned the inside to a rust stalactite landscape.
I dropped the tank, dumped it out. Poured in a gallon of fresh gas, swished it around and dumped it out. Seemed clean enough, no rust.
You might consider relocation for easier access.

Just a thought. :drunk2:
___
That setup is actually fairly easy to access from underneath. It's just really easy from the top, as everything is off whilst I work on the entire vehicle.
 

dlbleak

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Alright Paul, spill the beans. Whatcha workin on?
Looks like a Ford truck frame to me, but I could be wrong. Wouldn’t be the first time!
 

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