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Old 03-09-2019, 01:10 PM   #1
Steves46
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Default GAV Knob Question

I have been enjoying driving my 30 coupe however it seems my GAV knob wont stay set. I generally keep it a 1/4 turn from closed and as I am driving, I have to keep moving it back to my intial setting. I guess from the vibrations it slowly moves clockwise towards the closed position. I searched around to see if anyone else has delt with this but couldn't locate aby info. Appreciate any advice how to fix the minor glitch. Steve
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Old 03-09-2019, 01:29 PM   #2
J Franklin
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Default Re: GAV Knob Question

When it closes does it run worse? if not don't worry about it. you can also replace the grommet at the dash and make sure the GAV needle & seat assembly at the carb has the C clip installed.
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Old 03-09-2019, 01:33 PM   #3
Purdy Swoft
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Default Re: GAV Knob Question

I always replace the adjustment needle housing when the GAV setting gets too loose . The needle housing screws right into the side of the lower carburetor housing . and is easy to replace . Brattons lists this part number as 14000 Price $7.85
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Old 03-09-2019, 01:54 PM   #4
30 Closed Cab PU
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Default Re: GAV Knob Question

I will be following this closely. I have the same issue, after 5-10 minutes of driving the GAV migrates to fully closed, too lean. I tried replacing the grommet, still does it. I farmer fixed it for now by wedging in a round baking toothpick between the grommet and GAV Rod. Was going to see about a permanent fix this spring. Was also going to ask here what to try.
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Old 03-09-2019, 02:01 PM   #5
Bob C
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Default Re: GAV Knob Question

The little metal ring may be to loose and not allowing the housing to put enough pressure on the needle to keep it set.


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Old 03-09-2019, 02:08 PM   #6
Steves46
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Default Re: GAV Knob Question

Quote:
Originally Posted by J Franklin View Post
When it closes does it run worse? if not don't worry about it. you can also replace the grommet at the dash and make sure the GAV needle & seat assembly at the carb has the C clip installed.
Yes it runs worse for a couple of times I forgot about it migrating then the car starts running worse-I glance over and sure enough, the knob has closed. Will double check the grommet.
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Old 03-09-2019, 02:26 PM   #7
redmodelt
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Default Re: GAV Knob Question

In the distance past, there was an issue with where the needle passed thru the clamping area and the fix was to remove the little ring at the bottom. If your ring is missing replace the needle valve as suggested above. That little ring helps keeps pressure from the fingers on the needle so it stays where it is set at. The rubber grommet helps but is more for anti-vibration. Also, clocking the knob so the little projection is at the bottom when in running position. Few people realize that is a tiny counter weight, same with the knob on the junction box cover nut, made so if comes loose, tends to point down and not vibrate around and off.
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Old 03-09-2019, 07:44 PM   #8
Fred K-OR
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Default Re: GAV Knob Question

Quote:
Originally Posted by Bob C View Post
The little metal ring may be to loose and not allowing the housing to put enough pressure on the needle to keep it set.


Bob
Based on what little I know about this problem, but it sure seems like this is the solution. It has been mentioned above also.
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Old 03-09-2019, 08:05 PM   #9
Steves46
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Default Re: GAV Knob Question

I will double check and may go ahead and order a replacement ajustment needle housing as well.
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Old 03-10-2019, 03:27 PM   #10
100IH
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Default Re: GAV Knob Question

I seem to remember that some reproduction shafts had an issue with the knob loosening relative to the shaft. Might try getting it set and then put a vice grip on the shaft at the floor as a counter weight. Sort of like the little one wing nuts on the dash junction box.
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Old 03-11-2019, 07:42 AM   #11
DD931
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Default Re: GAV Knob Question

Yes, I would check to be sure that the knob isn't loose! When I brought my newly-acquired '30 coupe home I was annoyed that turning the GAV didn't have any effect on the engine. It seemed to turn OK, but no effect. Cut to the chase - the knob was turning on the threaded end of the shaft. Yes I felt stupid, but was glad to have an easy fix!!
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Old 03-11-2019, 10:20 AM   #12
Farrell In Vancouver
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Default Re: GAV Knob Question

I'll second DD931 they can come loose and mess with you.
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