#21  
Old 01-09-2022, 12:10 PM
wbnapier wbnapier is offline
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Location: Encinitas, CA
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On a freshly restored tri-power I had a a similar problem after opening the outboard carburetors.

I had to add a heavier duty torsion spring (from a 4bbl) on the rear carb so that the outboard carburetor butterflies would close completely. You need sufficient spring pressure to return all the butterflies to idle.

Mike told me I can tweak the lighter duty spring to get some more strength out of it too.

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1965 Pontiac GTO
455 w/ #48 Heads, '65 Tri-Power
Modern Muncie M22W
3.55 Rear Differential
  #22  
Old 01-13-2022, 03:01 PM
Tripower67 Tripower67 is offline
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Quote:
Originally Posted by Dick Boneske View Post
Have you looked to see that the fast idle cam is rotating clockwise as the engine warms? Iíve seen situations where the choke thermostatic spring is backwards, actually closing the choke, increasing idle speed.

Check that out before you do anything else.
Confirmed that it's set-up correctly and turns clockwise, lowering the idle cam position.

  #23  
Old 01-13-2022, 03:02 PM
Tripower67 Tripower67 is offline
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Quote:
Originally Posted by wbnapier View Post
On a freshly restored tri-power I had a a similar problem after opening the outboard carburetors.

I had to add a heavier duty torsion spring (from a 4bbl) on the rear carb so that the outboard carburetor butterflies would close completely. You need sufficient spring pressure to return all the butterflies to idle.

Mike told me I can tweak the lighter duty spring to get some more strength out of it too.
I did the hand test to feel for any suction on the secondaries and did not feel anything, I did re-seal them with DAG about a year ago. I might have heavier duty springs to be extra sure though.

Idle vac is also about 17in/hg, which seems too good for a major vac leak. Maybe not?

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