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Holley Secondaries

Chevelle_Nut

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My boat is a Chevy 4.3L with a Holley marine 4bbl. This is the only Holley I have, when do Holley secondaries kick in? Can I get them to work in the driveway or only under a load?
 

Nashville Cat

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Vacuum secondaries only open under load. Maybe a hand pump like a Mity-vac would open them ?
I would think a small V6 would need a 450 or 500 cfm carb ?
 

Chevelle_Nut

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Vacuum secondaries only open under load. Maybe a hand pump like a Mity-vac would open them ?
I would think a small V6 would need a 450 or 500 cfm carb ?
That is what I am reading too, Quadrajets don't do that.

This is a marine carb and intake, no vacuum ports, I wish there were so I could really dial the engine in
 

77cruiser

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It takes air flow there's a tube or orifice in the venturi to create vacuum to open the secondaries.
Q jets have an air valve just needs air flow, depending how tight the spring is set, they will open slightly by whacking it.
 

Nashville Cat

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Holley makes a marine 450 vacuum secondary carb that looks like it would be perfect. Only $1000 :eek:
 

Chevelle_Nut

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Holley makes a marine 450 vacuum secondary carb that looks like it would be perfect. Only $1000 :eek:
I will keep the one I have :)

It has been sitting since last summer. I ran a compression test nothing abnormal, 100 to 120 in all cylinders. Gapped plugs, set the timing and adjust the carb. Last years gas is running just fine.
 

68Chevele

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If you can feel a vs Carb open then they opening too soon. Last year I ran the FST vs carb on my 358 and it has the lightest spring in the pod (white) but I found after messing with the fine adjustment screw in the side of the pod the vs carb was quicker and faster with the screw turned in 2 1/2 turns in. A boat engine should pull that sec side open pretty fast, most likely you have the black spring in the pod. That spring will never ever let the sec side open all the way, it's that stiff.
 
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