Gasoline filters

[SeaEric]

This has probably been answered before, but I could not find the info in a "search" of the forums.

I own a gas powered sportfish boat- twin 454/340 HP Mercruisers. With the ethanol issue at hand, proper fuel filters are obviously more important than ever. The setup now has a Racor 500 as a primary and then a Fram PS3808 spin on as a secondary. I did some research on the Fram and could not identify what level of filtration they achieve- ie microns. The Fram is only described as a "Fuel/Water separator" on the web. Its not a very big filter, about the size of a coffee cup.

The Racor elements are available in 2, 10, or 30 micron. My question is: What micron # Racor should I use as the primary, given the additional Fram as a secondary? So far, the boat doesn't seem to have an existing fuel problem.

 

[Maynard Rupp]

That is a good question Eric. I looked at mine and have no clue. I installed Mercruiser spin ons to compliment my Crusader original equipment filters. Neither say anything about "microns". I haven't even heard of that topic in gas engine discussions. I guess that is a diesel engine thing. It sure would be nice to know mainly so your coarser filter could be the first.

 

[captddis]

I would use the 2 or 10 mic racors. My memory is fuzzy but the merc spin ons are fairly coarse like 38 micron.

 

[67hat34c]

if you have flow scan after the Racor then use the 30 otherwise use the 10, there is no need for a 2 on a gasoline engine. Cant see the need for the secondary filter as the racor is going to get everthing needed

 

[captddis]

I like a filter after the fuel pump, I have seen all kinds of junk come out of the pump as it ages. I have installed many floscans with 2 mic filters and never a problem.

 

[Maynard Rupp]

Most Crusaders have quadrajet carbs. They have a fine filter in a capsule on the carb where the fuel line goes in. So we have a Merccruiser spin on ahead of the Navman flow transducers, the original engine mounted filters, and the final filters in the quadrajets. Enough is enough.

 

[captddis]

Not all Qjets have the inlet filters and most AFB have none. I can't count the times I have had to take the top offf of a AFB and remove a small speck that was on the needle. Plus those engine filters will let water go through with out any problem. Do what you are comfortable with.

 

[Maynard Rupp]

Not all Qjets have the inlet filters and most AFB have none. I can't count the times I have had to take the top offf of a AFB and remove a small speck that was on the needle. Plus those engine filters will let water go through with out any problem. Do what you are comfortable with.

My spin on Merccruiser filters are supposed to be water seperators. Do you think I need more filtration? You may be right about the quadrajet filters, I don't have alot of experience with them, but all that I have seen have the little plastic line filters.

 

[captddis]

Maynard,
Maybe consider using the Racor spin on in place of the primary filter. They make one that fits the merc head. Dave