1957 Olds 98 accelerator issue. (371 Engine-Rochester Carb)

[pitman]

As we all know the accelerator is managed by linkages. I have tried and tried to adjust mine to smooth out the advance in throttle--but everything I have done has not solved my issue.  I assume the linkages are bent--worn--or whatever over time and it is likely causing my issue.  Can I install an aftermarket pedal assembly---OR LINKAGE REPLACEMENT--- to replace this old stuff and make it a pleasure to drive again?  If so who makes it--and where can I purchase such an item?  OR DOES ANYONE HAVE ANY SUGGESTIONS AS TO THE ADJUSTMENT THAT MAY BE TRICK I HAVE NOT TRIED?

       Thanks in advance for any help offered.

 

 

 

                                  Pitman

[carbking]

It is quite possible you do have worn linkage; however, a couple of thoughts:

 

(1) Several years ago when I was still restoring carbs, had a freshly "rebuilt" carb (Rochester 4-GC) come into the shop with exactly the same symptoms you describe. The rebuilder had incorrectly installed the secondary throttle link on the carburetor.

 

(2) Dozens of Rochester 4-GC carbs have come into the shop with the choke/fast idle linkage 180 degrees off.

 

So would suggest with your adjusting:

 

(1) Get a helper.

(2) Have the helper gently push down the accelerator petal while you observe all of the joints looking for a lack of instantaneous movement.

(3) If there is no visible issues, remove the throttle linkage from the carburetor.

(4) Work the accelerator petal checking for rough movement.

(5) If none, place a little tension on the link that attaches to the carb, and again work the petal checking for rough movement.

(6) If no issues, turn your attention to the carburetor.

 

(1) Get out your shop manual, and observe the pictures of the linkages on the carb, especially the choke/fast idle and pump linkage for correctness.

(2) Work the throttle slowly to wide open. The choke butterfly should initially close, then as you approach wide-open throttle, the choke butterfly should open slightly. The secondary throttle should NOT open, and the tension necessary to get to wide open throttle should increase about 1/2 way open as the secondary lockout prevents the secondary from opening.

(3) With your fingers, hold the choke butterfly wide open (vertical). Now work the throttle. The fast idle cam should drop. The secondary should now open, and the tension to open should remain relatively constant.

 

If these checks don't turn up any issues, give me a call at 573-392-7378 (9-4 Mon-Tues central time).

 

Jon.

Edited March 7, 2016 by carbking (see edit history)

[pitman]

Thanks for the suggestions. The issue,however, is definitely in the linkages. Accelerator pedal moves -- linkage lags--out of threads for adjustment at all points. Maybe I need to cut more threads and tighten up the adjustments? This is what I have in mind unless someone else offers a better solution. I would really prefer a cable over current linkages----but do not know if such a replacment is available.