This is on my 75 Ford F250, 351M, 4 speed, 3.73 Dana 60.
Ok. Since I hucked the AVS in the scrap barrel it's history. lol I have been trying to find out some information on this Holley 7002-1 4175 spread bore vacuum secondary, and I have somewhat.
It is a carburetor that is completely foreign to me. I have seen them on things before, but have no experience working on one.
Some of the things I have found out. They came originally with a 2 stage power valve. Evidently the first stage opens at one vacuum level for enrichment and the second stage opens at another level for yet more enrichment.
Also, it seems this carburetor may have reverse air screws from the "normal" Holley.
I am having two problems with it. One, the air mixture screws do not work right. The engine continues to run with the screws seated. In fact it gets better with the screws seated, as if I had some more threads and could turn them in more I could get it adjusted correctly.
Two, it has a pretty bad part throttle tip in hesitation or bog. This is only on the primary side. The secondaries come in fine. If I roll into the gas, it does ok.
I have the floats right, even though they are not adjustable. I have the accelerator pump right. The transition slots are not overly exposed.
So after all this blabbering, here is my question. Since I was unaware it had a dual stage power valve, it was replaced with a single stage 6.5. I have read that if you do that, you need to jump up a few sizes with the jets. Is this correct?
Could this also cause the tip in hesitation? It really runs great other than these two problems. I could drive it like this anywhere...and do, but it would be great to get it worked out.
I really need to try to get this worked out if possible because I do not have the money to just throw at a new carburetor, even though that's what I would love to do. Thanks.
Ok. Since I hucked the AVS in the scrap barrel it's history. lol I have been trying to find out some information on this Holley 7002-1 4175 spread bore vacuum secondary, and I have somewhat.
It is a carburetor that is completely foreign to me. I have seen them on things before, but have no experience working on one.
Some of the things I have found out. They came originally with a 2 stage power valve. Evidently the first stage opens at one vacuum level for enrichment and the second stage opens at another level for yet more enrichment.
Also, it seems this carburetor may have reverse air screws from the "normal" Holley.
I am having two problems with it. One, the air mixture screws do not work right. The engine continues to run with the screws seated. In fact it gets better with the screws seated, as if I had some more threads and could turn them in more I could get it adjusted correctly.
Two, it has a pretty bad part throttle tip in hesitation or bog. This is only on the primary side. The secondaries come in fine. If I roll into the gas, it does ok.
I have the floats right, even though they are not adjustable. I have the accelerator pump right. The transition slots are not overly exposed.
So after all this blabbering, here is my question. Since I was unaware it had a dual stage power valve, it was replaced with a single stage 6.5. I have read that if you do that, you need to jump up a few sizes with the jets. Is this correct?
Could this also cause the tip in hesitation? It really runs great other than these two problems. I could drive it like this anywhere...and do, but it would be great to get it worked out.
I really need to try to get this worked out if possible because I do not have the money to just throw at a new carburetor, even though that's what I would love to do. Thanks.
