fuel filter

[vinnytruck]

Hi Guys, My gas filter has been disconnected, it looks like for a while now, maybe years... So I am putting a inline filter. My question is would the truck have any problems with a filter before the fuel pump and a filter before the carb. I also have a filter on the pickup tube in the gas tank. I have the old style fuel pump. question #2: if this is not good (all these filters) whats better filter before the fuel pump or filter before the carb., thanks again VT

[WarrenD]

Mine has the original filter in the tank and an add on one between the pump and carb. After the pump will catch anything that might be roaming in the pump. All my old cars and trucks always their one and only fuel filter just before the carb.
I don't think you need one before the pump, the one in the tank should keep the lines clear.

[8543bob]

GOOD MORNING,
I like the filter before the pump, as it can catch anything that might be harfull to the inards of the pump.
Just my.02
GOOD LUCK BOB

[vinnytruck]

Thanks Warren and 8543, I was wondering because I dont want to happen to me what happened to the other guy, with stuff getting into his fuel pump and the rebuilders liabilty for a pump just rebuilt. My question still stands: will 2 filters effect the fuel delivery system? Thanks VT

[SOTVEN]

IMHO, THE STOCK FUEL PUMP HAS A STRONG SUCTION/PUSHING CAPACITY. GIVEN THAT YOUR TANK ISN'T FULL OF DEBRIS THAT WILL CLOG THE FILTERS VERY SOON, I WOULD SAY THAT YOU WILL NOT HAVE A PROBLEM WITH 2 FILTERS IN LINE. HOWEVER I FIND THIS AN OVERKILL. I HAVE THE IN-TANK FILTER, AND AN INLINE FILTER BEFORE THE PUMP RIGHT AFTER THE PETCOCK. I MUST SAY THAT PLENTY OF RUST PARTICLES FOUND THEIR WAY PAST THE IN-TANK FILTER. PERSONALLY, DEPENDING ON THE CONDITION OF YOUR TANK, I THINK CLEANING AND LINING THE TANK IS NECESSARY TO AVOID FILTER CLOGING. PUTING 2 FILTERS DOES NOT SOLVE MUCH. JUST MY 2 CENTS. GOOD LUCK

[vinnytruck]

sotven, thanks for the reply...My tank is new. I will go with the filter before the pump. connect the 2 parts of the carb. line (no filter). I always thought the carb. has to have a filter. I will try one for now. Does the carb. have a internal filter???? or one I can get at???? VT

[m37jarhead]

I won't pretend to know much about where in-line fuel filters should go and where they should not.
In any old vehicle you have a variety of situations to deal with before deciding where and how many
fuel filters you'll need.
Here's some thoughts to ponder on M37 fuel delivery sysytems:
New tank, old tank cleaned, old tank not cleaned?
Electric fuel pump or manuel pump or both?
How many fuel filters are currently in line; one in the tank and another OEM filter on the fire wall?
Have you considered a spin on "cannister" type fuel filter attached to the frame just forward of the tank?
(Usually before an electric pump.)
Are the fuel lines new or old? (Rusty lines are your ememy.)

For what it's worth, here's the setup on mine.
New fuel filter in the tank, cannister filter between the tank and the electric fuel pump, OEM filter on the firewall,
"see-through" barrell type filter betwee the manual pump and the carb. This was the setup on my other M37. I still
found trace rust particles in the see-through filter before the carb. That truck had a tank that was steam cleaned
and sealed but still had old lines. Don't know where all the crud came from but it never completely went away.
And, let's not even get started on ethanol mix fuels...............They will eventually destroy any old rubber parts
in your fuel system.
JB

[m-37Bruce]

Hey JB,
Did you clean/reline your tank, are you using a walbro/napa/wix pump screw on filter similar to Bill Wincapaw's? I'm leaning toward this setup. Still no start, but plenty of cranking and spark?

[m37jarhead]

Used a NAPA screw on canister typer filter. NAPA #3343 designed for fuel only.
This followed by a 24V electric pump. Both units mounted on inside left rear of frame
about 2' +/- from the gas tank.
The fuel filter screws onto an old cast aluminum oil filter brackett that I had on the shelf.
New ones are inexpensive and can be found at any auto parts store. You may have to buy fittings
to suit your needs.
Don't know what Bill's setup is but have seen similar on g741 posts.
The filters are not cheap. NAPA charged me $33.00 for their filter.
My fuel tank had been "boiled" or steam cleaned. That's when the pin holes
showed up and had to have them soldered. Now I'm not sure if
I had any kind of coating put into the tank after cleaning.
I'm sure that the rust particles that I saw in the clear filter just before the
carb. were from rust inside the fuel lines.
The filter system worked well; never had a hiccup with it but I did inspect/change
the filters regularly.
JB

[m-37Bruce]

Did you by-pass the mechanical pump?
Thanks 4 Your Help,

[m37jarhead]

I did not bypass the mechanical fuel pump. I mostly used the electric pump for priming the system
after the M had sat for a week or more. It had a bad habit of hard starting after the truck had
sat idle for a while. Adding the electric fuel pump to the system cured the problem.
Once the truck started and the mechanical pump took over, everything ran fine and the
electric pump was turned off.

Others on this site may have a solution to this typical M37 starting problem. I chose to get
the electric pump. It's also a handy gadget to have if your mechanical pump goes south.
Might also help in the event of vapor lock. (?) Nothing beats redundancy.
JB

[vargaspj]

The stock ETW1 carb has no internal fuel filter.
I'd have to go back and look in the manuals but I believe the original setup was the in-tank fuel filter which I think was discontinued and replaced by the sintered fuel filter assembly mounted on the regulator bracket in the engine compartment.
Every time you add an inline filter you have an additional pressure drop in the fuel line. As long as you don't drop the pressure at the carb inlet below what's required (I think 4-7 pounds) you should be OK and operating within specs. Pressure too low and the inlet fuel pressure can't lift the needle off the seat to keep the fuel level in the carb fuel bowl at the right level and you get intermittent stalling. Inlet fuel pressure too high and the needle won't seat and you force fuel into the bowl and you run rich.
Definitely have an inline filter right in front of the carb input. If you get any small contaminants in the carb inlet you can have big problems. The tech manuals list the fuel pressure required at the carburetor inlet for proper operation.

[powerwagontim]

Actually its the other way around, the regulator mounted filter was discontinued for the in tank one. The rest of your post sounds good though!
Tim

[m-37Bruce]

I did not bypass the mechanical fuel pump. I mostly used the electric pump for priming the system
after the M had sat for a week or more. It had a bad habit of hard starting after the truck had
sat idle for a while. Adding the electric fuel pump to the system cured the problem.
Once the truck started and the mechanical pump took over, everything ran fine and the
electric pump was turned off.

Others on this site may have a solution to this typical M37 starting problem. I chose to get
the electric pump. It's also a handy gadget to have if your mechanical pump goes south.
Might also help in the event of vapor lock. (?) Nothing beats redundancy.
JB

Hey JB, I was wondering where you mounted the on/off switch, dash, under seat?