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Re: Fuel System Restoration: Tanks to Carbs...

Posted: Wed Aug 14, 2019 10:04 pm
by jralbert
Assume you replaced the CG 11 filter at the mouth of some 4 bbl carbs. I don't think (not sure at all) whether Edelbrock uses those filters but the little buggers did exactly what you described to me sevl times (though at about 1800 rpm)

Re: Fuel System Restoration: Tanks to Carbs...

Posted: Thu Aug 15, 2019 5:19 pm
by JohnO
I still have the carter AFB’s has those filters but they have been removed.

Re: Fuel System Restoration: Tanks to Carbs...

Posted: Fri Aug 16, 2019 6:42 am
by ddependo
I put a fuel pressure gauge in line before carb, that way I can tell if it is a fuel delivery problem or carb problem.
Sometimes finding out what the problem is is finding out what is not.
Wayne

Re: Fuel System Restoration: Tanks to Carbs...

Posted: Fri Aug 16, 2019 2:08 pm
by Fastjeff
That's always the best way to eliminate one side of the problem (fuel or spark). The pressure gage has to be Teed in after the fuel pump, which can be a pain in some cases where all metal lines are used. I cut into the metal lines and added a NAPA all metal, in-line filter (cheap--ah-hem!) with A1 hoses on each side and doubled up miniature hose clamps. With these filters in place, it's a simple matter to Tee in a pressure gage with some extra rubber hoses and see what's happening.

You're looking for a CONSTANT 4 to 6 psig at a high cruising speed. If the pressure sags as the motor makes power, there's your problem. Next thing to do is figure out WHY the little darling is doing that to you.

Jeff

Re: Fuel System Restoration: Tanks to Carbs...

Posted: Fri Aug 16, 2019 3:39 pm
by ddependo
Jeff reminded me one time to check the "check valves" in the fuel lines from tank. They can get stopped up.
Wayne

Re: Fuel System Restoration: Tanks to Carbs...

Posted: Fri Aug 16, 2019 5:37 pm
by fpc310
Does anyone have a photo of what the anti siphon / check valve looks like? It seems they have a history of being problematic, but I’m not sure which part of the fuel system this is.

Re: Fuel System Restoration: Tanks to Carbs...

Posted: Sat Aug 17, 2019 6:44 am
by Fastjeff
No photo, but they are in the fittings where the fuel lines exit the tanks.

Jeff

PS: Don't tell anyone, but the PO tossed them out on mine so they never caused me any trouble.

Re: Fuel System Restoration: Tanks to Carbs...

Posted: Sat Aug 17, 2019 7:23 am
by ddependo
On my 73 model express they are after the fuel cut off.Between the perco filters and before the fuel pump.
Small brass fittings about 1 1/2 long.
Wayne

Re: Fuel System Restoration: Tanks to Carbs...

Posted: Sun Aug 18, 2019 8:55 pm
by JohnO
My check valve was removed from the problem side. On advice of another mechanic, I'm going back to spark. Might be the way I installed my distributor. I'm going to continue on that thread. Hopefully someone has an answer because this is perplexing. (Again, my screw up but how else do you learn)?

Re: Fuel System Restoration: Tanks to Carbs...

Posted: Tue Sep 03, 2019 9:18 pm
by JohnO
I finally found adapters at a random NAPA store while on another mission. Still contemplating replacing whole fuel system(winter project) I did finally figure out my problem, distributor springs too tight (see 318 ignition post).