is 3 fuel filters overkill ?

[lumpy]

Sent: 9/4/2008 6:17 AM

My coach is currently running 3 fuel filters. 1 on each tank before the mechanical fuel pump and 1 between the pump and the carb. I know the two on the fuel tanks are needed, but if I the fuel filters are doing there job pre pump side is the one to the carb really needed?

[denisondc]

Sent: 9/4/2008 8:34 AM

I dont care to have a filter between the pump and carb, because it involves having any rubber hoses, which can burn if there is a fuel leak that gets ignited. Originally I believe the mopar v8's all had metal lines from pump-to-carb. Some carbs had a tiny built-in filter where the fuel delivery line connects. If my carb had one of those, I would punch a hole through it. In my opinion its too small to be useful on a vintage vehicle.
Some fine silt will get through the typical filters. It will be very fine though, like rouge. Most of it will likely just get sucked through the jets and passages with the fuel and not cause any problem. When you take a carb apart for rebuilding, it will be seen as a reddish layer in the bottom of the float bowl.

I have an in-line filter just before the mechanical pump, in the unpressurized part of the fuel system. (I dont like to put a plastic filter in the pressurized part of the system). The filter is located beside the frame rail, ahead of the front tire - and is easy to reach by lying on the ground in front of the RV. It is the plastic kind that you can see into, to inspect for silt buildup.

If you have filters for each tank, are they in locations that are easy to reach, when it comes time to change them?

[lumpy]

Sent: 9/4/2008 9:55 AM

yes they are easy to get to , I changed them out , easy crawl to and change in 5 minutes.

[lumpy]

Sent: 9/4/2008 11:02 AM

Ok guys I just changed all 3 of them with the fram g2 filters that are clear to see what happens. I fired the old gal up and the filter by the carb began to fill right up without a problem , let it idle til warm and then gave her the juice. Brought the r.p.m.'s up to about 2500 and the filter did not hold fuel . It dropped to nothing but still ran good.  Should the fuel in the filter maintain level when at running speeds? or drop off ?
My first assumption is that I have a fuel delivery problem.

I will open up a new discussion based on this a little later.

Thanks

Mike

[denisondc]

Sent: 9/4/2008 12:35 PM

In warm weather I think it is common for a fuel filter to look like it is about empty. This is because the fuel vapor expands so readily. But the liquid part of whats in the filter should be flowing onward.

My technique for testing fuel flow isnt for everybody. With the engine idling, I unscrew a fuel line, or pull off a fuel hose coming from the pump (being careful that the stream doesnt spray onto a manifold or a spark plug wire), and I expect to get a nice gurgly stream of fuel squirting pulsing out of the line or hose from the pump. It should shoot out a couple of feet. If it only squirts out a few inches, and doesnt splatter all over the place - that indicates a fuel flow problem.

[lumpy]

Sent: 9/4/2008 1:09 PM

well I definitely have a flow problem , i can see the inlet opening on the filter and it is just a trickle to the filter. I am amazed the thing even runs. one other indication that should have given me a clue was the previous owner gave me a box of extra parts and in it was two used fuel pumps. I suspect I have a worn camshaft. Might have to go to the electric fuel pump.

[thebluesliner]

Sent: 9/4/2008 5:27 PM

I had a fuel flow problem with my rebuild. The fuel pump arm that runs on the cam was wore where it rubs on the cam it wasn't warn through but there was a good indentation on the arm. My Mechanic buddy told me to order one which I did but of course procrastinated and didn't put it on right away. Like you it was starving the motor for fuel. What a difference after installing the new one and not a very big job on the 318-3 although you may get wet with that precious liquid and spill a little on the ground