Fuel water separator / filter function

heli_av8tor

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Aug 8, 2016
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2
My 1995 Sea Ray, Mercruiser 4.3 has a Sierra International 18-7944 Fuel Water Separator Filter. If this filter removes water in the fuel where does it go?
Does the filter eventually become saturated with water?
How often should this filter be replaced?
 
Last edited:

bruceb58

Supreme Mariner
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Mar 5, 2006
Messages
30,454
Sinks to the bottom of the filter. You need to change at least annually. Never remove, dump contents and reinstall.
 

Grub54891

Vice Admiral
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Jun 17, 2012
Messages
5,908
If you just leave it there, it will eventually fill up with water if any is getting in. Or it will just plug up from debris as any filter does. As Bruce said, change it at seasons end as part of layup.
 

thumpar

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Jun 21, 2007
Messages
6,138
When you do change it fill it with fuel before you put it back on.
 

Grub54891

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Jun 17, 2012
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5,908
If your fuel pump is good it should not need any priming. Just put it on and run it. If it won't prime, the fuel pump is weak.
 

thumpar

Admiral
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Jun 21, 2007
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6,138
It is still easier to start with fuel in it, especial if it is a mechanical fuel pump.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
11,799
Fill it up & oil the gssket well...
BTW....watch those Sierra filters, I have had 2 in recent years that would not thread on the base; threads must not have been cut right. So before filling with gas try to see if it threads on first....
I might go back to the BRP ones I can get at my local dealer....
I tried the Raycor with the metal bowl for inboards. This is probably the best filter there is but it's a pain to get that bowl off the old one....
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
11,799
Fill it up & oil the gssket well...
BTW....watch those Sierra filters, I have had 2 in recent years that would not thread on the base; threads must not have been cut right. So before filling with gas try to see if it threads on first....
I might go back to the BRP ones I can get at my local dealer....
I tried the Raycor with the metal bowl for inboards. This is probably the best filter there is but it's a pain to get that bowl off the old one....
 
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