Vaccuum secondaries
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Cargo Master
Joined: Apr 2001
Posts: 2,364
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From: Eustis FL
Vaccuum secondaries
How do you know if you have vaccuum secondaries?
Does that mean there is no physical link to open the rear butterflies?
Mark
Ford started it; Ford will finish it!
Does that mean there is no physical link to open the rear butterflies?
Mark
Ford started it; Ford will finish it!
Posting Legend
Joined: Sep 2001
Posts: 30,255
Likes: 37
Vaccuum secondaries
When your engine is not running and you look down the carb with the choke open:
Operate the throttle linkage slowly to full open on the primaries. If the secondaries start to operate when the primaries are part way open, and come full open also with the primaries, you do NOT have vacuum secondaries. You have mechanical secondaries. This means you have a direct mechanical link between the primaries and secondaries.
On vacuum secondaries the secondaries are operated by sensing the airflow thru the primaries. There is a physical link to the primaries to make certain the secondaries close when the primaries close.
-Eric
[link:www.ford-trucks.com/guidelines.html|FTE Moderator]
over!
Operate the throttle linkage slowly to full open on the primaries. If the secondaries start to operate when the primaries are part way open, and come full open also with the primaries, you do NOT have vacuum secondaries. You have mechanical secondaries. This means you have a direct mechanical link between the primaries and secondaries.
On vacuum secondaries the secondaries are operated by sensing the airflow thru the primaries. There is a physical link to the primaries to make certain the secondaries close when the primaries close.
-Eric
[link:www.ford-trucks.com/guidelines.html|FTE Moderator]
over!
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Cargo Master
Joined: Apr 2001
Posts: 2,364
Likes: 3
From: Eustis FL
Vaccuum secondaries
Hmmm... My secondaries do not open with the primaries: Yet, when I turn the choke to lean, it releases the 'cam' holding back the secondary lever! Is this just so secondaries don't operate when engine is still cold???
Mark
Ford started it; Ford will finish it!
Mark
Ford started it; Ford will finish it!
Posting Legend
Joined: Sep 2001
Posts: 30,255
Likes: 37
Vaccuum secondaries
That's Right! That is observant. You wouldn't want the secondaries opening up and dumping "unenriched" mixture in when the engine was cold 
Keep moving those linkages and figuring out the interplay between them for a nice education. Some of those linkages have semi-explanatory names in the repair manuals.
According to your observations you must have vacuum secondaries also.
Keep moving those linkages and figuring out the interplay between them for a nice education. Some of those linkages have semi-explanatory names in the repair manuals.
According to your observations you must have vacuum secondaries also.
Posting Legend
Joined: Sep 2001
Posts: 30,255
Likes: 37
Vaccuum secondaries
Vacuum secondaries are the very best for street use unless you are very experienced in throttle control to eliminate bogs. I personally would not use mechanical secondaries for any kind of daily driver.
I use an Edelbrock 1406, 600cfm, vacuum/airflow actuated secondaries, electric choke carb on my 400 daily driver.
Lets see what proford460 has to say!
I use an Edelbrock 1406, 600cfm, vacuum/airflow actuated secondaries, electric choke carb on my 400 daily driver.
Lets see what proford460 has to say!
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Cargo Master
Joined: Apr 2001
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From: Eustis FL
Vaccuum secondaries
How hard is it to convert to electric choke? And, what point does the wire go to? Is it the temp sending unit?
Thanks!
Mark
Ford started it; Ford will finish it!
Thanks!
Mark
Ford started it; Ford will finish it!
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Posting Legend
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Vaccuum secondaries
On an electric choke the (red) wire goes to a point that is "hot" in the run position only. The other wire (black) is usually grounded. Edelbrock sells a kit to convert their carbs to electric choke.
I prefer a manual choke. The #$&% electric choke is always on at the wrong time.
I had a manual choke fixed up with a nice bright yellow light (dim at night) when it was on so that I wouldn't forget. Of course I LIKE to play with electricals :-)
I prefer a manual choke. The #$&% electric choke is always on at the wrong time.
I had a manual choke fixed up with a nice bright yellow light (dim at night) when it was on so that I wouldn't forget. Of course I LIKE to play with electricals :-)
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