vaccum secodaries

**DELTA~HOLIC** · 08-31-2010, 06:16 PM

I have a Holley Carb and the vaccum secondaries aren't opening. I had one of my buddies check them as i was WOT and they didnt open. Once he stuck his hand down there and opened them manually I gained an additional 500 RPM's. I took apart the diaphram and everything looked legit. He was saying I possibly need a lighter spring, but I would like your guys input. Thanks!

**MudPumper** · 08-31-2010, 06:18 PM

Mechanical Secondaries and call it a day....JMO

**FastRat** · 08-31-2010, 06:24 PM

yup...Holley sells a complete spring kit...it includes colored springs in different strengths

...you might be able to find it at Checkers, Auto Zone, Napa etc or else Summit, Jegs carry it...just sayin'

FastRat

**Sleeper CP** · 08-31-2010, 06:33 PM

Start with the mid-strength spring. Other than that a DP. I hate vac sec carbs on jet boats.

S CP

**Burnt Sticks** · 08-31-2010, 07:18 PM

There is a hole in the primary side of the main body down in the venturi. The air passing by this opens the secondaries. Make sure the hole is not plugged up. I have blown down the venturi with an compressed air and made them open.

**Quickjet** · 08-31-2010, 07:26 PM

Originally Posted by Sleeper CP

Start with the mid-strength spring. Other than that a DP. I hate vac sec carbs on jet boats.

S CP

Are you crazy!!!??? Vacum sec carbs work great on Jet boats. I used one for my Bahner. Everytime I unhooked it from the truck I would throw an old 3310 under the trailer tire to keep the thing from rolling out of my garage.

**Schi-502** · 08-31-2010, 07:28 PM

Lend me your boat. I'll fix it!

Nice ride. Been out lately?

**moneysucker** · 08-31-2010, 08:45 PM

Stick a small bolt through where the arm connects to the primaries so when you floor it the arm will open them manually.

**G-Body** · 08-31-2010, 10:50 PM

I have a 650 vacuum on my 305. I put the lightest spring in and it would not open all the way. I was swapping springs out and noticed the little ball bearing that slows the secondary opening so you dont get a bog.....you know the one that holley says never to take out. Well in my application taking it out worked out very well. Secondaries open every time now and I don`t even have a bog.

**jet460** · 08-31-2010, 11:01 PM

Originally Posted by Burnt Sticks

There is a hole in the primary side of the main body down in the venturi. The air passing by this opens the secondaries. Make sure the hole is not plugged up. I have blown down the venturi with an compressed air and made them open.

Mine did the same thing.
Plus, I switched to the lightest spring in the kit when I rebuilt my 4160's.

**DELTA~HOLIC** · 08-31-2010, 11:19 PM

Originally Posted by Schi-502

Lend me your boat. I'll fix it!

Nice ride. Been out lately?

Anytime Mark. I went out last Sat, how bout you?

**DELTA~HOLIC** · 08-31-2010, 11:23 PM

Thanks guys! I will fool around with it a little more to see if I can get them to open, if not I will just go mechanical. Seems thats the way to go!

**HammerDown** · 09-01-2010, 07:48 AM

Heck, you would have to pry my Holley VS carb from my dead cold hands before I would give it up.
Offers good cruising economy and it still hits hard when the go-pedal is punched down.

**splatter** · 09-01-2010, 08:31 AM

I had a stock 460 in a cruiser with a 850 dp on it. Performance wasn't an issue with an old heavy tub with a stock motor so I put a 750 vc on it for kicks. It didn't lose any top rpm and it cut fuel consumption by a bunch.

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