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Proper location of fuelwater filter

E

erich

Regular Contributor
"My 1989-90 454 Crusaders have

"My 1989-90 454 Crusaders have a fuel water separator filter mounted on the engines between the tank and the mechanical fuel pump. The Rochester Qjets also have a filter inside the inlet fitting. I seem to remember reading posts (Jeff or Rick?) indicating that the fuel/water separator filter should not be located between the pump and the tank, but between the pump and the carb. I can't locate these threads and not sure if that recommendation was for electric pumps only. Do I remember correctly, and, if so, what is the reason for this recommendation? I believe my setup is original from Silverton and has not caused any problems yet.


Thanks,
Erich"
 
"It's not usually a good i

"It's not usually a good idea to have pressurized fuel filters on a gas boat. I recall seeing the racor instructions to only use on the vacuum side of the pump as well. Safer, plus the pump sees only filtered fuel as well.
Also, any fuel flow sensor (Flowscan) will want to see filtered fuel."
 
"Dave is correct, I would not

"Dave is correct, I would not recommend putting a filter after the pump, for the very reasons Dave mentioned."
 
"ditto Dave & Rick. Mercru

"ditto Dave & Rick. Mercrusier and Sierra bot say install on suction line, between tank and fuel pump"
 
"OK, everyone agrees that my c

"OK, everyone agrees that my curreent setup with the fuel/water filter before the pump is correct. I wish I could find those older posts with what I thought recommended the opposite.

Thanks,
Erich"
 
"Virtually every car, boat or

"Virtually every car, boat or truck in existence has some type of fuel filter AFTER the fuel pump! (Think about it. Your Rochester carbs also have one, right?) But that little filter is a well-known engine killer--its dirt capacity is extremely limited, which means a blockage if too much crud comes through (and that can mean a burnt piston).

Y'all (was talking with my Southern buddy) may be confusing filters (fine separation) with water separators (coarse separation). Big difference. Put the latter before the fuel pump to protect it and eliminate water. Put a fuel filter AFTER the fuel pump to protect the carb and prevent vapor lock should a bunch of crud come through (and these are "evil-nol" days!)

Jeff"
 
"Jeff,

Are you saying that

"Jeff,

Are you saying that I should have another fine separation filter after the pump and before the carb? Something with more capacity than the filter in the carb housing?

If I were to add some brand of fuel flow meter, I believe most maniufacturers recommend having a filter before the fuel flow sensor to prevent crud from interferring with the sensor operation and also the sensors should be located close to the fuel tank. So should I add a 10 micron fuel/water filter to each engine fuel line just before the sensors? This would mean having 2 fuel water filters, one before and one after each sensor. What would do you say about that setup?

Thanks,
Erich"
 
"This is from the Racor web si

"This is from the Racor web site:

Note: Clear bowls are for outboard
applications only. Important - all
filters must be installed on the
suction (vacuum) side of the fuel
transfer pump.

On the Q-jet inlet filter; all the newer ones are coarse strainers, at best. they haven't used the sinstered bronze ones in decades. Paper ones may still be available but I haven't seen them in an OEM parts bag, ever.

For Jeff: where would you put the defining line (micron rating-wise) between fine and coarse when it comes to fuel filters?"
 
".."Are you saying that I

".."Are you saying that I should have another fine separation filter after the pump and before the carb? Something with more capacity than the filter in the carb housing? "

Exactly correct!

You need some kind of crud removing device before the fuel pump, but this is for LARGE crud, not fine stuff.

The defining sizes are: Coarse: 30 microns and higher. Fine: 10 microns.

Jeff"
 
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