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starback
11-14-2013, 10:46 AM
Greetings everyone!

I'm working through some fuel line issues on a 69 IIA SWB and have swapped the existing fuel filter, a metal bodied AC-DELCO GF61, with a clear plastic equivalent to find the fuel inside the fuel filter remains only half full (the filter is positioned horizontally).

It runs fine (knocking on wood), but I'm thinking that the filter should be full. Its a mechanical fuel pump. I've tightened the connections, removed and cleared the intake at the tank and cleaned the bowl. Still only half full no matter what i've done.

Do I keep at it because there is a air leak or let this go because it is what it is?

Also, I've read a suggestion to place another filter after the pump. Is this a good recommendation and would it be the same type as used before the pump?

Thanks in advance! These forums have been a great help. Thanks to the hosts and posters!
SafeAirOne
11-14-2013, 10:57 AM
I don't use one but from what I've seen of other folks that use them, this is pretty normal. I don't think I've seen one full.
I Leak Oil
11-14-2013, 11:11 AM
No, it won't be full. Sometimes at high revs it may even appear empty!
stomper
11-14-2013, 11:52 AM
The only time I have seen one full is if you turn the engine off, and manually pump the fuel lever to fill it. It will go back to half full once you start the engine though.
starback
11-14-2013, 12:07 PM
Awesome! Thanks so much for the quick response.
Peter
jac04
11-15-2013, 09:21 AM
Its a mechanical fuel pump. ... Also, I've read a suggestion to place another filter after the pump. Is this a good recommendation and would it be the same type as used before the pump?
Typically, mechanical fuel pumps don't like any restriction on the inlet. The original pump used a sediment bowl, which isn't very restrictive at all.
It is recommended to run a fuel filter on the discharge side of the fuel pump. Even though some carbs have an internal filter, you are better off catching anything in a separate filter that is easy to change. I highly recommend that you don't use a clear plastic filter, and you continue to use the metal-bodied GF61 (or equivalent metal filter). I have had the plastic filters fail, and they don't seem to hold up well to the hot underhood conditions.