Problem with Throttle Adjustment
Thread Starter
Le Mans Master
Joined: Jan 2000
Posts: 5,403
Likes: 3
From: Agoura CA
Problem with Throttle Adjustment
Currently my 66 will only get about half throttle when I push the pedal to the floor. The main problem that I see is that the arm which the pedal rests up against is already halfway down in its rest position. Meaning that I can pull it about half the length of its travel back towards me, but it doesnt actually catch and work the throttle until about the middle point in its travel. the previous owner in all their wisdom and skill adjusted at the carb so this halfway point in the arm travel is the idle point/closed butterflies. What do I need to do to fix this? Any diagrams around that show this system? My old factory service manuals arent great. I looked in there and it seems really tight and difficult to get to the linkage. Any suggestions?
Thanks
[Modified by VetteLT4, 5:32 PM 2/8/2004]
[Modified by VetteLT4, 5:33 PM 2/8/2004]
Thanks
[Modified by VetteLT4, 5:32 PM 2/8/2004]
[Modified by VetteLT4, 5:33 PM 2/8/2004]
Race Director
Joined: Aug 2001
Posts: 11,050
Likes: 0
St. Jude Donor '03 & '05
Re: Problem with Throttle Adjustment (VetteLT4)
The rod that goes to the carburetor has a threaded end towards the firewall. You may be able to take the play out by threading the swivel more towards the carburetor.
Melting Slicks
Joined: Oct 2001
Posts: 3,025
Likes: 12
From: Pleasant Grove AL
Re: Problem with Throttle Adjustment (VetteLT4)
You can correct the problem pretty easily, but you'll have to get under the car to do it. The throttle lever is attached to the pedal rod with a bolt that squeezes the lever on the rod. Loosen the bolt and have someone hold the pedal to the floor. At the same time, you need to open the carb all the way. Tighten the bolt. You should have the carb going back to idle position when the pedal is released. If you do it the other way around, you can get too much travel in the pedal and flooring it may break something on the carb linkage. The idle speed should be controled by the screw on the carb, ie no pressure from the throttle linkage. :auto:
Thread Starter
Le Mans Master
Joined: Jan 2000
Posts: 5,403
Likes: 3
From: Agoura CA
Re: Problem with Throttle Adjustment (62fuelie)
You can correct the problem pretty easily, but you'll have to get under the car to do it. The throttle lever is attached to the pedal rod with a bolt that squeezes the lever on the rod. Loosen the bolt and have someone hold the pedal to the floor. At the same time, you need to open the carb all the way. Tighten the bolt. You should have the carb going back to idle position when the pedal is released. If you do it the other way around, you can get too much travel in the pedal and flooring it may break something on the carb linkage. The idle speed should be controled by the screw on the carb, ie no pressure from the throttle linkage. :auto:
Melting Slicks
Joined: Oct 2001
Posts: 3,025
Likes: 12
From: Pleasant Grove AL
Re: Problem with Throttle Adjustment (VetteLT4)
The AIM doesn't show a very good picture, but it should be right on the left side of the trans tunnel. I'm more familiar with C1's. They have the same type of rig, but they can be accessed from under the hood. You may also have to adjust the threaded rod, but the first goal is to get full throw from the throttle lever. Once you look at it, everything will probably become clear. :auto:
Le Mans Master
Joined: Nov 2000
Posts: 7,246
Likes: 21
From: Going too fast over the hill. Iowa
Re: Problem with Throttle Adjustment (VetteLT4)
The adjustment on the 66 is at the rear of the LH valve cover where the throttle pivot sticks out of the "firewall"/dash. There is a bolt and nut that clamps the pivot shaft. Loosen it a little. Remove the throttle return spring. Put a weight on the loud pedal - just enough to hold it against the carpet. Pull the throttle wide open. Tighten the pivot bolt. Replace the spring. Hard pressure in to the carpet will give you wide open throttle (WOT).
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Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan
Re: Problem with Throttle Adjustment (magicv8)
The real solution is probably a little more tedious. The shaft from the accelerator pedal has a flat on the end of it where the clamp on the end of the lever bolts on, and the clamp has a matching flat. Chances are that the lever clamp has been loose for so long that the "flat" feature on the lever and shaft has been rounded off from wear, and the fit has become sloppy as a result. To fix it properly, you'll probably have to replace the shaft AND the lever, so both have correctly-matching "flats" in order to get full travel with no slop at the connection. :thumbs:
Thread Starter
Le Mans Master
Joined: Jan 2000
Posts: 5,403
Likes: 3
From: Agoura CA
Re: Problem with Throttle Adjustment (62fuelie)
there isnt any good pictures or diagrams around is there? sure would be helpful to know what im supposed to see when i crawl up under there. i saw there is one on corvette central, but its rather small.
Team Owner
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
Re: Problem with Throttle Adjustment (VetteLT4)
You may also have a problem with your linkage rod being in the wrong "hole" in the throttle arm on your carburetor. If the problem John described isn't present, maybe you can move the adjustable linkage rod closer to the throttle shaft on the carburetor to get more "throw".
Melting Slicks
Joined: Oct 2001
Posts: 3,025
Likes: 12
From: Pleasant Grove AL
Re: Problem with Throttle Adjustment (VetteLT4)
The AIM has a fair picture. The one in my 67 version shows the flat on the accelerator rod. I think once you get under there and look, the problem will be obvious. :auto:
Thread Starter
Le Mans Master
Joined: Jan 2000
Posts: 5,403
Likes: 3
From: Agoura CA
Re: Problem with Throttle Adjustment (62fuelie)
ill crawl under there this weekend and see what i find. hopefully it will be clear, but either way i gotta get this fixed. whats a corvette with only half throttle???
