Carb issue
Thread Starter
Instructor
Joined: Jul 2005
Posts: 234
Likes: 2
From: Fernandina Beach FL
Carb issue
Hey folks. Having a problem with, I think, my carb adjustment.
I have a '65 stock 327/300 with a Carter AFB. When I press the accelerator all the way to the floor quickly, the car stumbles and sometimes backfires.
It only happens when I do it quickly and under load. I checked the streams from the accelerator pump and they look healthy.
It seems like the problem is that the secondaries are opening too quickly. My understanding of the AFB is that they are controlled by weights and cannot be adjusted. Any thoughts?
I have a '65 stock 327/300 with a Carter AFB. When I press the accelerator all the way to the floor quickly, the car stumbles and sometimes backfires.
It only happens when I do it quickly and under load. I checked the streams from the accelerator pump and they look healthy. It seems like the problem is that the secondaries are opening too quickly. My understanding of the AFB is that they are controlled by weights and cannot be adjusted. Any thoughts?
Intermediate
Joined: Jun 2004
Posts: 31
Likes: 0
From: moorpark ca
Sounds more like an ignition problem. Lack of gas when you punch it open may bog down but I would not think it would back fire. If it backfires out the exhaust then it implies late timing. Like maybe the distributor weights are hanging or the vacuum diaphram on the distributor is ruptured? Just a guess.
Al Welch
Al Welch
Thread Starter
Instructor
Joined: Jul 2005
Posts: 234
Likes: 2
From: Fernandina Beach FL
Thanks for the recommendations on checking the timing. I did some investigation myself and also came to that conclusion. 
I plan to adjust the total this weekend using Lars' tech papers.
I plan to adjust the total this weekend using Lars' tech papers.
Thread Starter
Instructor
Joined: Jul 2005
Posts: 234
Likes: 2
From: Fernandina Beach FL
Update. Well, I checked the timing this weekend. It looks like my distributor is all jacked up. I set the initial timing at 8 BTDC per the manual.(it was already close)
I could never get more than about 24 total to come in before 3500 rpm. That was as high as I wanted to go.
The real issue is the vacuum advance. At idle, when I reconnected the vacuum line, the timing was at about 34*.
When I took a look at the distributor, I could pull the shaft upwards at least a quarter inch or so and when I rotated the centrifugal weights, they did not spring back. Looks like I have some work to do!
I could never get more than about 24 total to come in before 3500 rpm. That was as high as I wanted to go.
The real issue is the vacuum advance. At idle, when I reconnected the vacuum line, the timing was at about 34*.
When I took a look at the distributor, I could pull the shaft upwards at least a quarter inch or so and when I rotated the centrifugal weights, they did not spring back. Looks like I have some work to do!
