Are My Secondaries Open? Help
Thread Starter
Intermediate
Joined: Mar 2010
Posts: 34
Likes: 0
Are My Secondaries Open? Help
'73BB Stock Q-Jet
So when I pull my accelerator linkage WOT with the engine off and look down the secondary airvalve the secondaries only crack open about 10 degrees. Should they crack open 90 degrees at WOT or just open slightly?
So when I pull my accelerator linkage WOT with the engine off and look down the secondary airvalve the secondaries only crack open about 10 degrees. Should they crack open 90 degrees at WOT or just open slightly?
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
Have someone sit in the car and mash the pedal all the way down and check the opening of the throttle blades. Both primary and secondary should be open a full 90 degrees. If not you are not getting full throttle.
Le Mans Master
Joined: Dec 2007
Posts: 6,422
Likes: 591
From: McHenry Illinois
I agree with Gordon, but you need to make sure the choke is open enough to release the lock bar on the right side of the seconde=ary throttle shaft. You can trip it by hand for testing.
Thread Starter
Intermediate
Joined: Mar 2010
Posts: 34
Likes: 0
ok I did that and it still opens up the same distance as when I pull the throttle lever back as far as it can go which puts the accelerator pump pin all the way in and still only cracks the secondaries.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
If it has started to open, it is very close to being completely open. The secondary plates open with the last bit of travel of the cable/linkage. You may be able to get them fully open with an adjustment of the cable end at the carb mounting point. If not, you will have to adjust (bend) the accelerator bracket or fit a shim under the cable end at the accel pedal in order to get a bit more travel. You then need to make sure that the cable/linkage still fully releases at a "no throttle" condition.
Burning Brakes
Joined: Dec 2005
Posts: 992
Likes: 56
From: Baldwinsville, NY
Crescent wrench, close the jaws down on the accelerator bracket and bent the bracket a small amount. Test with someone moving the accelerator peddle. A little goes a long way and make adjustments with no load on the accelerator peddle.
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Tech Contributor
Joined: Aug 1999
Posts: 14,373
Likes: 6,371
From: At my Bar drinking and wrenching in Lafayette Colorado
The current version of my Q-Jet Setup paper has an entire section on this issue and how to fix it. Paper available by e-mail request.
Lars
V8Fastcars@msn.com
Lars
V8Fastcars@msn.com
