Holley 4781 850 DP - Chevelle Tech
Troubleshooting Diagnosing problems done here.

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post #1 of 4 (permalink) Old Oct 12th, 19, 8:14 AM Thread Starter
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Holley 4781 850 DP

I have a 4781-2 and a new 4781C. With the brown secondary pump cam set in hole “1, throttle hangs up in both carbs. They both work fine in Slot 2. I’m wondering if this is unique to me or do others have this problem.
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post #2 of 4 (permalink) Old Oct 12th, 19, 8:47 AM
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Re: Holley 4781 850 DP

You may have other problems, the 4781-2 carb is nearly 45 years old. Check for play in the throttle shafts and any other loving parts.

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post #3 of 4 (permalink) Old Oct 12th, 19, 11:44 AM
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Re: Holley 4781 850 DP

4781-3 here. Brown cam in 1 and works perfect. I use a little silicone grease on the cams.

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post #4 of 4 (permalink) Old Oct 12th, 19, 1:08 PM
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Re: Holley 4781 850 DP

That is nothing new.

Clean and lube the cam, then lube it again whenever it sticks again. Or, get a stronger return spring.

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