Air in fuel lines

[Mike Vinci]

I recently started catching air in my fuel system.  All component of the fuel system are less than five years old (tanks, lines, valves,etc)  The Racors were not catching air but the secondary filter on the engine was.  The fuel filter would be down quite a bit on the secondary.  To try to narrow things down I bypassed the secondary, changed the primary to a small micron, and ran the motor.  I don’t seem to be getting air anymore.  My throughs are possibly a hairline crack in the filter assembly, or I am using the wrong filter.  I did take the two hoses on either side of the secondary filter along with the filter and assembly itself and pressure test it and spray it down with soap.  I know the system is normally under vacuum not pressure but figured its worth a shot.  Below is a picture of what model QSM11 I have along with the filter im using.

Topic

[Clark Leighs]

Check the filter seals between the filter body and the filter element.    THey should be replaced each and every time you change filters.   THey can harden a bit or take an impression from their metal contacts and unless you line those up perfectly they will will improperly seal next time. 

Of course the filter element must be tightened properly or maybe the seal will fail to seal fully. I don’t mean cranking the daylights out of it but a GOOD snug tightening by hand.

 

Do you wet the seals, both sides, with fuel or oil?     Failure to do that may also mean the seal does not

really seal well.

[Author]

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