GAV Problem

B

brianogilchrist

Junior Member
My GAV has limited movement - from about 11 o'clock to 2 o'clock and it will not hold any position in between. It's not working at all I guess. The choke works fine and the engine starts and runs great with no backfiring or black exhaust. I have a Zenith carb and am using zero ethanol gas and MMO. I'm a novice and learning as I go. I've checked the Service Bulletins, Les Andrews and Victor Page books and Ford Barn but I can't find how to repair it. Also there are no clubs near me. I'm afraid to start taking it apart not really knowing what I'm looking for. Can anyone point me in the right direction or perhaps tell me what the fix is? Thank you in advance.
 
There isn't too much to that valve. If you decide to take it apart, be careful with your wrench size on the brass hex part. I've found some peculiar sizes there, and it's easy to booger up the brass.

Once you get it out you'll get a pretty clear picture of how the thing works, and probably what your problem is.

Your problem might be the retainer ring at the bottom of the valve, if you have a repro. Some guys just remove those without consequence.

Don't be afraid to work on your Model A. Each time you do you'll learn something about it and feel more confident in driving and repairing it.
 
Pull the sleeve up to inspect the joint of the needle for the GAV. You should have two nice flat halves that join together. I've seen some needles that have worn quite a bit at the flat part, and maybe that's the movement you feel at the knob.
 
I think that Ray hits the nail on the head in post #2 Usually the ring at the bottom of the needle housing has been removed, this has been my experience. Remove the needle housing and check. There are different wrench sizes that fit this part, depending on month of manufacture or whether the part is reproduction. I can narrow it down to three possibilities 7/16, 13/32 and sometimes 11 mm. Unless you have access to some used carb parts, the ring isn't offered in any of my catalogs. I usually just replace the needle housing for a quick repair Bratton lists this part for $7.85 Snyder lists this part for $7.80. good luck. If all of the parts are present on your needle housing, you may can squeeze it with pliers to tighten the fit of the needle in relatrion to the housing.
 
Thank you all for the help. Your descriptions told me what to look for and also Snyder's and Bratton's have good diagrams. Looks like a fairly easy fix to me. By the way, I forgot to mention in the original post that I started on this because I don't think I'm getting the mileage I should and maybe I don't have as much power as I should. Thank's again.
 
You must log in or register to reply here.
Back
Top