Author Topic: How to adjust the choke  (Read 3893 times)

Offline Flippo

  • Newbie
  • *
  • Posts: 1
How to adjust the choke
« on: March 24, 2011, 02:47:00 PM »
Hi,

i have a m4mc quadrajet working on my 1979 Trans Am with Olds 403 Engine. When the engine is cold, the choke is to rich. Is it possible to adjust the "richness" of the choke? (The exhaust seems to smoke black)
When the engine is warm and the carb opens the choke, the engine rpm raises a little. (No smoke any more) It is for me a sign that the choke gives to much fuel to the engine. How can i adjust that ?
I have checked the front vacuum bracke, it works fine.

Hope someone can help me.

Philipp

Offline Toronado

  • Carb lover
  • ***
  • Posts: 113
Re: How to adjust the choke
« Reply #1 on: March 24, 2011, 09:01:20 PM »
The choke is easy to adjust there is three scerws you loosen on the hoke coil housing, then you car turn it to rich or lean, it says on it which way is rich and which way is lean.

Allso check the idle mixture screws to make sure there tuned right,

How is your choke operating, how much does it open when you start is from cold?
Is it all the way open when the engine is warm?


Offline Cliff Ruggles

  • Administrator
  • Qjet Hero
  • *****
  • Posts: 5435
Re: How to adjust the choke
« Reply #2 on: March 26, 2011, 03:34:04 AM »
The choke adjustment only controls how long it stays on. 

Rich or lean at start-up is controlled by the choke pull-off.  Those models are adjustable with a screw and spring. 

Make sure to test the pull-off to make sure it holds vacuum, the rubber diaphrams go bad and will cause a rich condition at start-up as they don't unload the choke far enough.....Cliff

Offline Schurkey

  • Carb lover
  • ***
  • Posts: 157
Demand compensation from Communist China for the damage done by the Virus Originating in the Wuhan Lab, released (intentionally or negligently) into the world in 2019 (VOWL-19).  Trillions of dollars, plus direct compensation to individuals for medical bills, and "wrongful death" settlements.