Holley Carb Woes - DCDoug Pay Attention (Long Post)
 

DCDoug, we have pretty much the same engines, the exact same carbs (Holley 4160/Vac Secondaries), and we use the same gasoline -- so this is going to happen to you, it's just a matter of time. I've actually been waiting for it to happen, but when it did, even I was taken aback by the swiftness and ferocity at which it attacked my engine's performance. I'm talking about the Holley Zinc/Ethanol Clog and it's been all over the car forums for quite some time. Do you remember a couple of weeks ago I wrote that I had taken a long, slow speed, drive? The car and engine behaved beautifully. It then sat in the garage for a week or so, untouched. When I then started it up it ran horribly rough and would not even hold an idle. I mean it was bad. BAD, BAD, BAD – I mean, BAD. The only way I could keep it running was by tapping the throttle (thus having the accelerator pump squirt). I was stumped -- how can a car run beautifully right before you turn it off, and than run horribly when you start it up? I figured the low speed drive had fouled the plugs, so I pulled them. Sure enough, they were covered in black carbon... so I replace them. And WTF, might as well replace the MSD cap and rotor too (which looked a little bad as well), remembering to bend the rotor prong up a little bit. Well, at the speed I work that took about two days... and had no effect whatsoever on the problem. Still exactly the same -- bad stumbling, rough, can't hold an idle, pathetic and undrivable. Then I start thinking "out of the box" with stuff like Lykin's "you've wiped a lobe -- in fact Pat, you've wiped 8 lobes all at once even with the car not running -- see, I told you so." Or maybe the coil went bad, or maybe the MSD box has an intermittent fault, or I developed a monster vacuum leak through the manifold gasket overnight, etc. Well, I figure the likelihood of all that is small, and If I rev the engine hard, it sounds pretty good and strong if you can just get out of the idle circuit... so it must be the Holley Zinc/Ethanol Clog. How the heck does a carb clog up just sitting for a week in the garage? I don't know, but it does. And I've heard rumors that the amount of ethanol that is in our gas is wayyy higher than the 10% or 15% that is claimed. Evidently that ethanol combines with the zinc in the Holley carbs to make a wonderful clog that can appear literally out of nowhere. It will happen to you sooner or later, so here's how you clear it out without having to pull your carb off the manifold. BTW, the secondaries on our 4160 carbs have an idle circuit as well (mostly to keep the gas fresh in the bowl), but you just can't adjust it -- you still have to clean it out though. If you look down the top of your carb you will see your air bleeds (two per barrel, eight in total) outside are idle, inside are main. Blast carb cleaner down the bleeds and then follow it up with a blast of compressed air down through them to clear them all out. It's a very simple fix, but you can spend a lot of time chasing it down. Our 4160s idle rich to begin with. But when they're clogged and you keep using the squirter to dump gas on them you can carbon up your plugs pretty quickly and then you start thinking it's electrical, etc. So, when you go out one morning and start your car up and it runs so bad that you literally can’t believe it, clean your bleeds before you do anything else. Anyway, that's your handy "tip for the day." Here's two shots of me blowing out the air bleeds just so you know what they are:

http://www.clubcobra.com/photopost/d...irbleed001.jpg

http://www.clubcobra.com/photopost/d...irbleed002.jpg

That carb is just screaming out for a "Stubstack" Much better throttle response.

http://www.knfilters.com/Racing/stubstacks.htm


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As a newbie, I've got time before I hit that wall, but great tip. Is it the same for new and old hollies? Same zinc alloy used now? I am thinking of messing around with a 3255 and am just curious.

I'm not sure. But I am told that if you call Holley up and ask them about the issue they will point you to one of their aluminum jobs which apparently tolerates the high ethanol content much better.

Interesting. I don't know of any Ethanol free stations near me. I have a Ford Motorsport 351W 385hp motor with a Holley.

I wonder if there are any recommended additives or sprays which would let the carb live?

Jack

This is nothing more than yet another manufactured opportunity to show off your clean engine bay. Best way to cure HollyZinc-itis is to GO DRIVE IT!:LOL:

Yep, I use carburetor cleaner and compressed air on the entire car. Keeps it clean as a whistle.;) I, too, would like an answer to Jack's question on whether there is any "magic goo" that doesn't do more harm than good.

The Holleys have emulsion tubes too, inside the metering blocks and sometimes they can get some debris that will plug up one or more of the very small passages. Squirting a little carb cleaner in the air bleeds as pictured on a regular basis is the cheapest tuneup you can do.

Patrickt - Hey, are you suggesting it might be too long for me to absorb in one sitting?

"Holley Carb Woes - DCDoug Pay Attention (Long Post)":LOL:

I only fell asleep once. :rolleyes:

Of course not; I was just looking out for you.;) A friend from the Mustang forum sent me this link from last year about the same subject.
http://www.allfordmustangs.com/forum...-problems.html

Someone needs a manicure. :LOL:

Choke? Aren't those for "sissies." :p

You have no idea how bad my car sounded. I was seriously tempted to take an audio of it and post it, but instead I concentrated on fixing it instead. I was starting to think it was something bad. The car sounded horrific. Now I wish I had -- listening to something is sometimes worth more than a thousand words.

Yep.


And BTW, Patrick, if ANYONE could wipe the lobes off a cam with the engine shut down, it would be you. :LOL:

The same problems have been baffling me for quite some time with my 4150 series. Would never have believed it. I'll try your fix. Maybe get an aluminum carb.

That's why I posted it.:cool: I'll go back to bashing all non-ERA cars tomorrow.;)

Hey, how about getting a matching aluminum car to go along with that aluminum carb. :p

"Wipe the lobes off a cam"? Is that a euphemism or something? :LOL:

What hoses are you running Pat??
 

patrickt Pat are you running ANY rubber hoses from the fuel tank to the carb? Where are your fuel filters at and is there ANy rubber hoses after it?
Pat over the last 1.5 years there has been a problem popping up with lawnmowers, tractors, COBRAS, and racecars with idle problem. It doesn't matter if it's a carb or FI system. Injector fare better because of the extra fine screens on the inlet side of them. The rubber is breaking down inside the hose and mirco particals are clogging up everything. Sometimes the spes can be seen and are black, brown, or off white with a good magnetifling glass. All lines in my car are SS but where the fuel pumps go to there mounting plate. I have had to replace the hose all ready. You may need to look at any rubber hose on the fuel system needing replacement if this problem pops up again. As far as coatings on Holley carbs. I have not seen this coating problem happen with new carbs. I have seen problem with old carbs and the coatings are missing or peeling off.

Fuel filter at the back adjacent to the tank; rubber hoses on each side. Another rubber hose at the fuel pump (pics below). Will there be anything visible on the outside of the hose to tip me off?

http://www.clubcobra.com/photopost/d...uelline001.jpg

http://www.clubcobra.com/photopost/d...uelline002.jpg

Patrickt,

No, the outside of the hose will look just like it always did. I put a glass type fuel filter right before my carb and only had about a 3" rubber line to connect it to the carb. I have had problems with my weed eater, lawnmowers, and tractor cutting out and that was what it was.

Ron :(

I always put fuel filters on my lawn mower, snow blower, edger, etc etc. I put them on all my kids tools too. Once you do this they will run fine for the life of the device. 99.9% of all small engine problems are dirty carbs. Because these are such small engines, they require very little fuel. As a result the jets in the carb are about the diameter of a human hair and the clog up very very easily. Put a fuel filter on it and it will start right up and run great until the unit simply wears out from age. Small engine repair shops make their whole living by "fixing" peoples lawn mowers when it is nothing more than dirty/clogged carbs.


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