SBC 350 Possible issues with Carb?

[Burbinator86]

So I will give a quick rundown of what I have and what the issues seem to be. I have a 1986 GMC suburban with a small block 350 and a 700R4. The engine is completely stock and so is the exhaust. The only thing that has been changed is a Edelbrock 1406 carburetor that I just finished cleaning/rebuilding this last Saturday.

Now, for the issues, which I hadn’t experienced before I rebuilt the carb.

When first starting up it acts like it has to clear itself out for about 90 seconds and shakes like crazy like it’s running on a couple of cylinders instead of all eight. After it warms up, it seems to clear out. Then while driving it as an example this morning, I noticed it at about 40-45 mph in third gear, when I let off at anything over about 2000 RPM it pops and sputters out the exhaust like crazy.

It’s never done it before and has only happened since I rebuilt the carburetor. And if it helps, my adjustment screws are about two and three-quarter turns out. It was at 2 1/8 but it didn’t make a difference.

It has brand new spark plug wires, and the cap, rotor, and spark plugs are about six months old

Any help is greatly appreciated. I get most young guys want a pop tune, and for their car to run like crap, but I really would rather not.

 

[75gmck25]

Edelbrock’s are sensitive to fuel pressure (keep to about 5psi or lower) and float level. My guess is that one of those is off and it’s throwing in too much fuel and screwing up your mixture.

 

[Burbinator86]

Edelbrock’s are sensitive to fuel pressure (keep to about 5psi or lower) and float level. My guess is that one of those is off and it’s throwing in too much fuel and screwing up your mixture.

Do you have any suggestion for a inexpensive fuel pressure regulator?

 

[Sad Sack]

Do you have any suggestion for a inexpensive fuel pressure regulator?

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[MIMS GT]

I fixed my Edelbrock issues with a Holley .

 

[75gmck25]

A stock mechanical pump should be within Edelbrock specs, so I would verify the pressure and then go from there. I have never purchased a pressure regulator, so I don’t have any recommendation.

The link provided in the previous post is for a gauge, not a pressure regulator. I used a similar one to verify my pressure and it was very simple to install inline.

The gauge I bought used all barbed connections for rubber line, so I ran the gauge connection line up and out of the engine compartment and taped the gauge on the windshield (looked a little redneck). I thought I was losing fuel pressure at higher rpm, but was able to verify that the pressure stayed about the same all the time.

 

[Terlingueno]

A stock mechanical pump should be within Edelbrock specs, so I would verify the pressure and then go from there. I have never purchased a pressure regulator, so I don’t have any recommendation.

The link provided in the previous post is for a gauge, not a pressure regulator. I used a similar one to verify my pressure and it was very simple to install inline.

The gauge I bought used all barbed connections for rubber line, so I ran the gauge connection line up and out of the engine compartment and taped the gauge on the windshield (looked a little redneck). I thought I was losing fuel pressure at higher rpm, but was able to verify that the pressure stayed about the same all the time.

I use an Edelbrock fuel pressure regulator. I tested my ACDelco fuel pump and it is 8lbs and caused issues with my Eddy 1405

The first regulator was a Meester Gasket, but it crapped out after a little over a year, replaced with Eddy

 

[Ricko1966]

New fuel pump are almost always to high pressure for Edelbrocks. But since you didn't have any of these issues before the rebuild. I'd be more Inclined to think you did something wrong during the rebuild. Also curious as to what else if anything was done at the same time.

 

[hey mister]

If you had no issues before the carb rebuild...if..
Then I would agree with too much fuel getting in.
Maybe not related to fuel pressure but due to float level too high.
Drop the float level just a whisker and run it.
You may have to adjust it a couple times.

That is if it has a float...I'm not familiar with that carb.

 

[ali_c20]

A stock mechanical pump should be within Edelbrock specs, so I would verify the pressure and then go from there. I have never purchased a pressure regulator, so I don’t have any recommendation.

The link provided in the previous post is for a gauge, not a pressure regulator. I used a similar one to verify my pressure and it was very simple to install inline.

The gauge I bought used all barbed connections for rubber line, so I ran the gauge connection line up and out of the engine compartment and taped the gauge on the windshield (looked a little redneck). I thought I was losing fuel pressure at higher rpm, but was able to verify that the pressure stayed about the same all the time.

My Carter stock replacement pump on my K5 puts out 9psi.
I run fuel pressure regulators in the 100$ price range. Quality regulators can be rebuild.

 

[CheemsK1500]

Does your 1406 still have an electric choke? On one 305 I have a 1406 on, the choke coil needs to be moved from time to time, or the truck will run like crap. Also check your vacuum advance line for any damage and look for vacuum leaks in general. I’m currently running an OE style fuel pump on this engine and it doesn’t seem fuel starved by any means.

 

[Kheughens]

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[Poodlehead]

It has brand new spark plug wires, and the cap, rotor, and spark plugs are about six months old

When replacing the cap, make sure you transfer the middle GND from the coil to the middle pin under the cap. It will run good enough to get you around, but not run right. I dealt with that issue for a long time...