fuel filter question

[76bonanza]

I have a fuel filter under bed were my line transitions to frame and one under hood after pump. My question is do you need both I would think the one before the pump would be good enuf. Whats your guys take on this?

[rage'nrat638]

well i run 4
one after each tank (3 tanks)
one at the carb.
i like the plastic ones so i can see the junk in it.
with all the gas problems these days, nothing worst than sucking crap in the carb. mark

[Oldtruckfanatic]

All the fuel pump manufacturers want you to use a filter in both places. I can tell you this, When the diaphram goes bad in a fuel pump the chunks of rubber will travel to the carb if there isn't a filter there to stop it.

[TugOwar]

I have one out of the tank (currently in the bed - bleh) and one at the carb. Also the plastic ones. Cheap, easy to change and yeah, you can see the junk in it.

[TugOwar]

On a side note, and not meaning to hijack the thread, but OTF reminded me of this.

I had a 283 in a 66 chevy 1/2 ton years ago. Went out one morning to crank it and something didn't feel quite right, like she didn't want to turn over. Got to checking and discovered the reason. The fuel pump diaphram had gone bad and it sat there over night and filled the crankcase with gas!
That was a freaky feeling, knowing just the right spark might have set her off big time! lol

[Oldtruckfanatic]

Yep lol seen that before. If you check your oil and it's more than the last time you checked it's fuel pump time. another good reason to check your oil.

[Longhorn Man]

putting a filter between the tank and pump can help to induce vapor lock.
A restriction south of the pump will cause the pump to work harder, and this reduces the pressure in the fule line. (think when you try and suck a thick milk shake through a straw) The more restriction, the more the pressure drops in the line.
By reducing pressure, you are also reducing the boiling point. Even if you only reduce it by one degree, you are adding to a pre-existing problem. This is one of the reasons moden cars have the fuel pump in the tank, and also why the fuel pressure is now 40 - 95 psi... raising the pressure raises the boiling point... notice, new cars never have vapor lock problems.

[TugOwar]

Good point Andy.

I run two filters on the beast mainly for one reason. The gas tank is home made, steel and several years old. Was that way when I bought the truck and I can't afford to replace it just yet. The amount of rust that comes out of this thing is unbelievable.

For the time being I'll sacrifice a little fuel pressure to keep the yuk out of the carb. If I start having vapor lock problems then I'll have to rethink things for sure.