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Old 07-26-2024, 10:22 PM   #1
AngryPirate
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Holley 2300 2 barrel carburetor question

I'm installing this carb on my GMC and I noticed the left fuel inlet has a flare fitting but the other side, which I assume is meant if you have a fuel source on the other side of the engine, is wide open.

Do I need to buy and install some plug into this?

Thanks for any help.
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Old 07-26-2024, 11:55 PM   #2
geezer#99
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Re: Holley 2300 2 barrel carburetor question

Wide open!
I’ve never seen one wide open.
Unless someone has been drilling.
Take a pic in there for us.
Is this a brand new carb.
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Old 07-27-2024, 12:31 AM   #3
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Re: Holley 2300 2 barrel carburetor question

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Originally Posted by geezer#99 View Post
Wide open!
I’ve never seen one wide open.
Unless someone has been drilling.
Take a pic in there for us.
Is this a brand new carb.
Holley factory refurbished, so basically new, straight from Holley.

There is nothing in the right side.

I’ll take a pic tomorrow but I’ve been trying to look at other people’s carbs and it looks like nothing is there but it seems wrong to just have one side open like that… but maybe you have to drill the other side if you want to use the right side?
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Old 07-27-2024, 01:22 AM   #4
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Re: Holley 2300 2 barrel carburetor question

This the best I can do at the moment ..
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Old 07-27-2024, 09:56 AM   #5
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Re: Holley 2300 2 barrel carburetor question

A reman from Holley is set to bolt on and go.
That blank hole was used on some multi-carb motors. No need to plug it.
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Old 07-27-2024, 10:27 AM   #6
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Re: Holley 2300 2 barrel carburetor question

Quote:
Originally Posted by geezer#99 View Post
A reman from Holley is set to bolt on and go.
That blank hole was used on some multi-carb motors. No need to plug it.
Thank you!
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Old 09-07-2024, 03:08 PM   #7
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Re: Holley 2300 2 barrel carburetor question

So, I finally got to get back into it.

I got one of those spark plug piston stop bolts to put into the #1 cylinder to find TDC.

I think somethings off.

The yellow lines are the stops and the middle is supposedly TDC.

Also, I noticed that the vacuum coming out of the metering port at idle (it was 1000 rpm which I know is high for these engines) was reading 5 in Hg.

I would’ve expected that to be closer to zero ¯\_(ツ)_/¯

Any thoughts on the TDC being off (at least I think it’s considered off. Ignore the positioning needle, I would’ve expected the pulley “1” marking to match the orange line.

Thanks for any ideas / help.
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Old 09-07-2024, 05:10 PM   #8
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Re: Holley 2300 2 barrel carburetor question

Your orange line isn’t exactly half way. It should be closer to the one.
But it’s close enough. You need to move your pointer so it’s accurate.
Your 5hg of vacuum is because at 1000 rpm you’ve uncovered the ported vacuum port enough to show some vacuum. The port you have your tester hooked to is the ported (timed) port.

Why the high idle at 1000rpm?

Last edited by geezer#99; 09-07-2024 at 05:21 PM.
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Old 09-07-2024, 06:05 PM   #9
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Re: Holley 2300 2 barrel carburetor question

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Originally Posted by geezer#99 View Post
Your orange line isn’t exactly half way. It should be closer to the one.
But it’s close enough. You need to move your pointer so it’s accurate.
Your 5hg of vacuum is because at 1000 rpm you’ve uncovered the ported vacuum port enough to show some vacuum. The port you have your tester hooked to is the ported (timed) port.

Why the high idle at 1000rpm?
So, it might be the angle of the picture, but I basically took a piece of paper, marked the 2 yellow lines on the paper, took the paper out, folded in half then put a mark on the paper at the fold, then re-laid the paper strip down on the pulley and marked the orange on the pulley.

Fair enough on the 1000 rpm and the 5 hg.and you're correct, that is the timed vacuum port. At proper idle I would expect it to be 0 or near 0.

The 1000 rpm is because I can't get anything set up correctly and the lowest I can get it to idle (via adjusting the dist) has it at 1000 rpm. Other adjustments to the dist have it running rough-stalling and backfiring or the other direction ramps it up to 2500 rpm, which is frightening.

The idle adjustment screw on the carb it 100% out, so nothing I can do there.

Question, the pin/pointer down by the pulley seems static, like it can't be moved. Am I missing something?

Thanks for the response. I'm super frustrated with this carb switch over and it could be that the higher performance carb has just revealed issues with the ignition timing or they are both messed up or set incorrectly.

As far as the Holley 500, I believe I have it all set to stock, initial configuration which should be close enough to start dialing things in, but I am WAY far from that.
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Old 09-07-2024, 06:40 PM   #10
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Re: Holley 2300 2 barrel carburetor question

You likely need to make a new pointer. I doubt your original one bends. Get creative.
Do you have the choke high idle screw adjusted all the way out?
Do you have any other vac ports in use or capped off?
What distributor you got?
Do you have a better further away pic of carb and top of motor?
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Old 09-07-2024, 06:56 PM   #11
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Re: Holley 2300 2 barrel carburetor question

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Originally Posted by geezer#99 View Post
You likely need to make a new pointer. I doubt your original one bends. Get creative.
Do you have the choke high idle screw adjusted all the way out?
Do you have any other vac ports in use or capped off?
What distributor you got?
Do you have a better further away pic of carb and top of motor?
Hey geezer!

It’s a manual cable choke. No specific choke idle screw. Just the regular idle screw and it’s all the way out, so it’s doing nothing at the moment.
All other vacuum ports are capped.
Stock dist with a Pertronix igniter II that was working with the old carb.

Pics attached.
Thanks for looking!
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Old 09-07-2024, 07:02 PM   #12
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Re: Holley 2300 2 barrel carburetor question

Check again.
The high idle screw faces to the back of the carb. It’s a Phillips head screw.
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Old 09-07-2024, 07:49 PM   #13
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Re: Holley 2300 2 barrel carburetor question

In regards to the camshaft pulley pointer, the reason I was manually re-checking for TDC is bc I was worried that the timing chain jumped a tooth.
It may have done so before I put the new chain on since I stamped everything so everything would go back as it was. “As it was” could’ve been off.

Anyhow, I’ll go searching the backside of the carb…
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Old 09-07-2024, 08:28 PM   #14
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Re: Holley 2300 2 barrel carburetor question

Look right back and below the choke lever. Can’t miss it.
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Old 09-07-2024, 09:02 PM   #15
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Re: Holley 2300 2 barrel carburetor question

Found it, I think.

If that’s it, it’s not engaged at all.
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Old 09-07-2024, 09:31 PM   #16
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Re: Holley 2300 2 barrel carburetor question

Well that’s not it!
Is your carb mounted to the intake with an adaptor?
I’ve seen gaskets hang up on the throttle plate before.
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Old 09-07-2024, 09:32 PM   #17
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Re: Holley 2300 2 barrel carburetor question

Before you put the carb back on take a pic of the throttle plate.
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Old 09-08-2024, 05:16 PM   #18
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Re: Holley 2300 2 barrel carburetor question

Hey geezer.

Yeah, it’s an adapter plate.
I pulled the adapter off and test mounted everything on the bench and I didn’t see any hang up on the flaps.

I’m starting to think it’s a bad refurb from Holley or my timing chain is off by a tooth or so.

I’m getting a fuel pressure regulator with a gauge on it to be sure the carb is getting 6 psi as well.

Just to remove another variable.

Here’s some pics of the base plate of the carb and the adapter plate mounted with the gasket.
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Old 09-08-2024, 06:12 PM   #19
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Re: Holley 2300 2 barrel carburetor question

Throttle plates are quite black.
It mighta been flooding a bit.
Check your float level.
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