inline fuel filters

[old cool]

I'm still attempting to smooth out my 250 inline engine when sitting at a light; in gear; clutch in; idling at 550 to 650 rpm. I realize from previous posts this slight vibration could be accelerator pump issues, plug wire, plug, float adjustment, etc. My questions today are about fuel filters. Between the fuel pump and carb, the PO installed a 3" GM or Delco type canister filter (within a few inches of the pump). There is also the original stone filter in the carb itself. Is it a good idea to have two filters? And here's the dumber question, is the stone filter positioned with the cone facing the fuel source or carb? When I first got the truck, I removed it without paying attention to position but logically faced cone toward fuel source.
NOTE: when testing the stone filter, I blew through it both directions. The air moved more freely when blowing into cone side; more restricted when I blew through the flatter side. Should there have been any restriction regardless of which side you blow through?

[PGSigns]

The cone side goes to the source. The cone increases the surface area for the fuel to flow through. I would change out the canister filter for one of the large see through plastic filters and get rid of the stone filter. And then turn up the idle some.
Jimmy

[Captainfab]

On my DD, a '68 C10 with a 250, I have a Wix 33032 filter just before the pump and a paper filter in the fuel inlet to the carb. I see no reason to not run 2 fuel filters. Many performance applications do.

[thelawdoc]

My understanding is that the sintered bronze filter or some other 10 micron filter should go into the carb inlet, with a 100 micron filter between the fuel tank and the fuel pump. Isn't the purpose of the 10 micron bronze filter that of keeping the needle and seat clear? Boy, these filters can be confusing.

[PGSigns]

The new small micron filters are more for keeping fuel injectors clean. Your needle and seat has about a .060 hole in it to open so nothing in the micron range that get by a filter will clog it. The OP was looking for ideas on chasing down an issue and my suggestion was to ensure the filters are not restricting the fuel flow. He had two potential fuel flow restrictions in the line from the pump to the carb. If the pump diaphram is getting weak the pump may not be pushing enough fuel through the two filters to keep the engine happy. This was a way to test it.
Jimmy