Mpls Funk

Hi all,

Thanks to the encouragement from many of you, I have decided to jump in with both feet and try to rebuild my carburetor myself. It is a Holley 4150...650 CFM double pumper (installed on a 1970 small block). I have had the car for 19 years and I have never rebuilt the carb...late this summer the car would not even start and we would not even get fuel coming out of the squirters...so I'm guessing this carb is really messed up!

I have successfully removed it from the car and removed both fuel bowls and the various things attached to the fuel bowls.

I just removed the two "squirters" and I believe there are supposed to be small needle valves under the squirter that should "fall out" when you tip the carb upside down. However, mine do not just fall out...they appear to be stuck. Any suggestions of how to get those little buggers out?

Second question...some of the gaskets really stuck to the metal and did not come totally off. My understanding is that I should not scrape them with something metal (like a flat blade screwdriver) as it's not good to scratch the metal surfaces, correct? so then I tried a plastic putty knife/scraper...but that isn't getting much off. Will most of this gasket remnant come off from soaking in the Chem-Dip?

Thanks for your help!

gerry72

The needle valves usually do just drop out, but you might have to tap the carb body to dislodge them. If they are varnished in place, you may have to soak the carb to unstick them. You have the old brown paper gaskets and they were notorious for their tenacity in adhering to the metal surfaces. There is a spray gasket remover (high in toluene) that will dissolve the gaskets making it easy to brush and scrape them off. You can use a metal scraper (or a small filed down old screwdriver since you are talking very narrow gaskets) to remove the gasket residue. Just be careful and don't apply gouging force in scraping the gaskets. They should be pretty soft after a chemical treatment. I have not used the current Chemdip formula but I hear it is nothing like the old formula, which I believe was primarily alien spit. I still have a can of the old stuff and I can say it would dissolve the gaskets. The new stuff will probably help but, again, I hear it is not nearly as aggressive.

Mpls Funk

So how bad is this chem dip stuff? I have been putting the small parts in the basket that is included in the can, letting it soak over-night with the cover 95% back on, and leaving it in the garage.

Now I have the main body and bottom plate to do, and they won't fit in the basket or the pail that the Chem-Dip came in. So I'm going to have to put the parts in a bigger bucket and then pour the Chem-Dip into the bucket. I then likely don't have a cover to cover it up nicely like I did with the original pail...and, it's getting quite cool over-night now in Mpls. So...I'm a little concerned about the fumes. If I leave it in the basement, in the mechanical/furnace room...will that be bad to leave it uncovered in the house? Or, if I put it out in the garage, will this stuff work less well if the temps in the garage get down to 40 or so?

You are right, this Chem-Dip does clean some stuff up, but it certainly didn't take care of the gasket remnants. So if this stuff is not that strong to begin with, I would hate to leave it in the garage at cooler temps and risk it working even less effectively! But obviously want to be safe with this first!

Appreciate any advice.

20mercury

hope this might help:

http://www.superchevy.com/how-to/45798/

and another:


Corvette Magazine online had one I used, but it looks like it has been deleted.

I have rebuilt my Holley and other carbs many times. Few suggestions:
*use a spray carb cleaner in a can with a straw and spray into all of the holes, ect. a spray can will force the cleaner throughout the carb.
*do not use any hard objects to clean out any holes as you do not want to enlarge the holes.
*after you spray a couple of cans of carb cleaner everywhere, let it soak and then blow out everything with an air compressor. follow the directions on soak time, and since the vapors are pretty light, I would do this outside or with good ventilation.
*carb cleaner will not hurt any metal parts, but avoid soaking any rubber parts in carb cleaner.
*I usually clean any sticking residual gasket material with a pocket knife carefully. as said above, be careful as you do not want to nick the metal and cause a leak point.
*you only want to take apart what is described in the links, you hopefully do not need to take everything apart. particularly, I would avoid taking the butterfly valves apart unless you just have to since the set screws have minimal threads.
*zip has a nice holley rebuild kit.
*there are other links as to how to tune the Holley after you rebuild it. Lars does a good one.

http://www.corvette-restoration.com/...arb_Tuning.pdf

to an old fogey like me, carbs are simple, fuel injection is complicated

Holley rebuild is quite doable if you read the directions, Quadrajets are a bit more complicated as I understand it.

Mpls Funk

So - still making progress...got the main body soaked, fuel bowls soaked...now all that's left is still some pesky sticky gaskets and the bottom base plate.

Is there anything on that bottom base plate (the part that actually mounts to the intake) that cannot be soaked in the chem-dip? Including the linkages and such on the sides?

Will also take any recommendations to get the remaining gasket material off???

Bel

You might consider changing the floats out to a Nitrophyl. I did this on my rebuild Double Pumper. It was recommended over the stock due to E-10 Fuel. Just a thought.

Mpls Funk

I solved the problem of the sticking gaskets and thought I would share with the group as it's pretty simple and effective.

Get a brass polishing wheel for a Dremmel...and either use it in a Dremmel, or put it in a drill. Works great...does not cut into the metal, but cleans/polishes it very nicely! It might take a couple wheels to get it done (I will need 2), but at $4 each....it's a winner in my book.

20mercury

good to know thanks!

Mpls Funk

Ok...making progress. Have the carb torn apart and cleaned...

In the video referenced above, they show a red plastic thing going into the bottom of the fuel bowls. When I took my carb apart, there was no such thing there. In fact, there was some metal thing. I've attached a picture here:
IMG_9371 by JMW_32, on Flickr

Do I need to somehow get this metal part out and put the plastic part in, or is the metal part somehow a replacement for the plastic things? Any help would be greatly appreciated!

gerry72

The rubber part actually superseded the metal check ball in production. They are both check valves in blocking fuel flow to allow fuel to enter the pump chamber and block it from leaving through that passage.

You can't replace a metal check valve with the rubber part, so you just keep the metal ball and retainer as is, which is a far better and more durable design than the rubber valve.

Mpls Funk

Awesome - thank you so much!