Holley 4 Barrel, Carb Secondaries Not Opening

greg82255

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Hello,

I did a 2 to 4 barrel swap over the winter and I just took my boat out to the lake today. I wasn't getting any more performance out of the motor so I took off the flame arrestor and took a look at the carb. I had my dad move the throttle back and forth while I looked, and I noticed that the carb secondaries weren't opening... so I am only running on 2 barrels. I am wondering how I can get the secondaries to open? I posted a picture of what appears to be the linkage to the secondaries. I'm not sure of the serial #, its a holley 600 cfm 4 barrel that came from National Carburetors on Ebay.
 

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jtmarten

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Re: Holley 4 Barrel, Carb Secondaries Not Opening

You have a vac secondary 600, you'll never get the secondaries to open without a load, even running at the dock in N revving it.
The only way to tell if they're opening or not is to have someone watch the linkage as you're running on the lake. If they don't open, you probably need to get a secondary spring kit. Has multiple springs to fine-tune the opening point. To make life easier, get a quick kit too. It replaces the cover on the right side (facing up) and makes changing secondary springs so much easier.
I had to play around with the secondary on my jetboat's Holley 750. Got it setup where they'd open at 3800rpm so I could cruise on the primaries all day long.

A trick I used many years ago when running Holley 4160's, you can put a little screw in the secondary linkage towards the bottom front, so the linkage arm from the mains hits it around 3/4 throttle. It'll crack the secondary butterflies and force them open sooner. I used this on my '64 Falcon 'vert, I don't know how effective it would be in a marine application. (Best to setup the vac 2nds with the proper spring!)
 

HT32BSX115

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Re: Holley 4 Barrel, Carb Secondaries Not Opening

Howdy,


The 4160 is one of the best carbs ever made.... (IMHO)


Holley still sells them new (I just bought one!)


Read the following info on the 4160. near the end of the article, there's some discussion on vacuum secondaries that should answer most of your questions.

http://www.holley.com/data/Products/Technical/199R8108-2.pdf


Cheers,


Rick
 

Camo Joe

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Re: Holley 4 Barrel, Carb Secondaries Not Opening

vacuum Thats the key.........Make sure it has no vacuum leaks.....Check the engine vacuum also........make sure the valves and timing are adjusted correctly........If the engine has the power the secondaries will open or end up as exhaust.........lol
 

greg82255

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Re: Holley 4 Barrel, Carb Secondaries Not Opening

How do I check to see if there are any vacuum leaks? Also how do I check the engine vacuum? I know there are a few vacuum ports on the carb, a few came with black caps on them and a few did not. If these ports are not plugged could that be the problem?
 

jtmarten

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Re: Holley 4 Barrel, Carb Secondaries Not Opening

If these ports are not plugged could that be the problem?

Uhhhhhmmmmmmmmmm, yes. HUGE vac leak. You'll never build enough vac to pop the secondaries with that size leak.
If you're on a carb learning curve, get with the Holley tech support guys for pro-level guidance. You could easily blow yourself up if you don't know how to setup the carb properly. You can't just throw on a new/different carb without lots of setup, and I certainly wouldn't rely on an ebay rebuilder/reseller to have a carb setup correctly. Each application will be slightly different, so you have to know what you're doing to get the setup right.

The fuel system in an enclosed bilge is nothing to take lightly.
 

greg82255

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Re: Holley 4 Barrel, Carb Secondaries Not Opening

Thanks for the help. I'll get on the phone with Holley tech support while I'm at the dock and have them walk me through what needs to be done.
 

Camo Joe

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Re: Holley 4 Barrel, Carb Secondaries Not Opening

Uhhhhhmmmmmmmmmm, yes. HUGE vac leak. You'll never build enough vac to pop the secondaries with that size leak.
If you're on a carb learning curve, get with the Holley tech support guys for pro-level guidance. You could easily blow yourself up if you don't know how to setup the carb properly. You can't just throw on a new/different carb without lots of setup, and I certainly wouldn't rely on an ebay rebuilder/reseller to have a carb setup correctly. Each application will be slightly different, so you have to know what you're doing to get the setup right.

The fuel system in an enclosed bilge is nothing to take lightly.


I second that motion..............all vacuum ports must be capped or be routed to something that is operated by vacuum........like the vacuum advance on the distributor.........pvc valve etc.
 

John_S

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Re: Holley 4 Barrel, Carb Secondaries Not Opening

I second that motion..............all vacuum ports must be capped or be routed to something that is operated by vacuum........like the vacuum advance on the distributor.........pvc valve etc.

Yes,...... but no vacuum advance in a boat, and pvc is only in late model.

Typically, only a hose barb above the butterflies would be used for mech fuel pump watch port. Otherwise, just cap them all. Any that lead to below the butterflies, that can be used to hook a vacuum gauge to. Cap it after.
 

Camo Joe

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Re: Holley 4 Barrel, Carb Secondaries Not Opening

Yes,...... but no vacuum advance in a boat, and pvc is only in late model.

Typically, only a hose barb above the butterflies would be used for mech fuel pump watch port. Otherwise, just cap them all. Any that lead to below the butterflies, that can be used to hook a vacuum gauge to. Cap it after.

True........true................

I think the vacuum gauge should read about 16-17 at the correct idle..........not sure of the engine condition though............a vacuum guage can tell you lots about whats going on with an engine.........
 

Camo Joe

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Re: Holley 4 Barrel, Carb Secondaries Not Opening

greg82255 is gonna out run everything on the water when this carb problem is fixed.....................if it was doing 30 it will do 60+............hold on to your hat..............
 

greg82255

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Re: Holley 4 Barrel, Carb Secondaries Not Opening

I was doing 50.... lol
 

greg82255

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Re: Holley 4 Barrel, Carb Secondaries Not Opening

How fast do you think I'm gonna go? Its a 19 ft checkmate.. I had a Rochester 2 barrel on there last year and was doing 50, and now with this new carb I am doing 50 and the secondaries haven't opened yet..
 

John_S

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Re: Holley 4 Barrel, Carb Secondaries Not Opening

I am betting they are opening. Not going to get the same performance on only 300cfm. If the upgrade (including intake) was good for 15-20hp, about 1-2mph. You can get that much variation in day to day running.
 

jtmarten

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Re: Holley 4 Barrel, Carb Secondaries Not Opening

Your Roch was probably 450-500cfm, you're gonna gain very little. You will, however, gain fuel economy if you setup the secondaries to open above 3500rpm, that way you can plane up, and cruise all day long @ 3200-3400 on the primaries.
If you combined the carb with a good intake (looks like you have a stock 4V intake) you'll gain more (maybe 3-4mph). Takes more than 1 mod to gain speed in a boat. You'll need: better intake, good water jacketed headers (big $$), head work (valves, P&P, rockers), and higher compression all working together to really see results.
Your hull will 'hit the wall' at some speed, from there on it'll cost $1000 or more per mph gain.
 

John_S

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Re: Holley 4 Barrel, Carb Secondaries Not Opening

Your Roch was probably 450-500cfm, you're gonna gain very little. You will, however, gain fuel economy if you setup the secondaries to open above 3500rpm, that way you can plane up, and cruise all day long @ 3200-3400 on the primaries.
If you combined the carb with a good intake (looks like you have a stock 4V intake) you'll gain more (maybe 3-4mph). Takes more than 1 mod to gain speed in a boat. You'll need: better intake, good water jacketed headers (big $$), head work (valves, P&P, rockers), and higher compression all working together to really see results.
Your hull will 'hit the wall' at some speed, from there on it'll cost $1000 or more per mph gain.

It looked to me to be an Edelbrock Performer intake, which would be slightly improved over the low-profile 2 brl intake. Mercarbs were in the 375-425cfm range. Not sure about the rochester 2brls, but thought mercarbs were derived from them???
 

a70eliminator

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Re: Holley 4 Barrel, Carb Secondaries Not Opening

You'll be hitting over 60........on the oil pressure gauge lol lol lol.
 

greg82255

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Re: Holley 4 Barrel, Carb Secondaries Not Opening

It is an Edelbrock performer intake. I did change the exhaust from the stock log manifolds to the GLM pro flow center risers, or whatever they call them. The ones that supposedly separate exhaust pulses. Someone gave me those for free so I haven't had to spend much $ besides the carb and intake. Just had to pay for new gaskets and some other odds and ends.
 

jtmarten

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Re: Holley 4 Barrel, Carb Secondaries Not Opening

It looked to me to be an Edelbrock Performer intake, which would be slightly improved over the low-profile 2 brl intake. Mercarbs were in the 375-425cfm range. Not sure about the rochester 2brls, but thought mercarbs were derived from them???

Ah, I should have looked closer. Painting an Edelbrock is what threw me. Polishing, yes; painting , ehhhh, fail.


The carb/intake/exhaust should bring it to mid-50s. Was the 50mph measured by speedo, or GPS? Speedos tend to be off by quite a bit. On GPS I'm running 56, 62 on speedo.
 

lonemust

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Re: Holley 4 Barrel, Carb Secondaries Not Opening

If you got vaccum ports on the carb open, I be willing to bet you have idle problems too. You should also push the throttle to wot and make sure the pri-sec link rod is pushing on the sec lever. It has to push them open a little before the vaccum will pull them open the rest of the way. I agree with other post 4160 and 4150 both are good carbs. I have a 4160 on my truck with an edle preformer int. Made a big dif in it. Yours looks like the advenger offroad series.
 
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