1967 427 Holley 2300C Carburetor issue?

[Richard M.]

I have this over at CF too so I can get as many eyes as possible on this one. Thanks for your help.

Please check out this clip in real time so you can listen in on my problem. I feel I have a problem carburetor condition going on and could use some guidance. It has a hard stumble when I blip the throttle from idle. Feathering it helps and accelerator pump is working, Maybe it needs adjustment. Could it be the Power Valve, or something blocked up inside? This is a new Holley 2300C. I'm more familiar with Carters than Holleys. I don't want to start doing things and make it worse.

The idle mixture(not idle adjust I verbalized it the clip) are at about 1 1/2 to 2 turns out from stop. I reached maximum vacuum at these settings, however I don't seem to get much variation of vacuum when I adjust the right bank.

TO SKIP THE CRAP IN THE BEGINNING AND TO GET RIGHT TO THE STUMBLE MOVE TO ABOUT 5:50 IN THE CLIP. But there's important data from the start to identify what I have set up.

https://youtu.be/92Tlj_vfxy8

Thanks,
Rich
p.s. I got interrupted for a hour when our black(appropriate color) Cocker Spaniel named "HOLLY"(appropriate name) sneaked out the open gate where I had my engine coolant outlet hose running. She showed up later just moping along back to the field out back from 60 heavily wooded acres beyond. This after a exhaustive search by my wife, son and I and all of our neighbors and friends.

[Richard M.]

Re: 1967 427 Holley 2300C Carburetor issue?

Follow up, I tried adjusting the accelerator pump to give a quicker squirt, maybe that's it, but I ran out of gas on restart then flooded it trying to restart after tanking it up and then drained the battery.

On the charger and drying out the intake saturated fuel with throttles wide open for a while.

Also, when I had it running again after the video earlier, I see the right side venturi is profusely dripping fuel at higher RPM's, not vaporizing. What the heck is going on? It's a brand new Holley.

[Richard M.]

Re: 1967 427 Holley 2300C Carburetor issue?

This carb is coming off(plus front to get at the center) in the morning. Suspect accelerator check ball problem and debris somewhere. Others have had accel pump problems too......HERE

2nd Clip Available in a half hour.

https://youtu.be/qqW3P9kJmcw

[Stuart F.]

Re: 1967 427 Holley 2300C Carburetor issue?

Rich;

Just a preliminary off the cuff comment; your concern may or may not be over blown (at this point in your assembly). I have often had AFB's do the same thing when sitting still idling, specially when engine is fully warmed. Wait until you have the car together and out running on the road under load before you conclude you have a big problem, or at least on a chassis Dino. Adjust it now as best you can.

I'll submit this as my initial impression until I have a chance to listen to your recording more carefully.

p.s. I noticed your center carb doesn't have an idle vent. Also, don't forget the end carbs also have a low speed idle function.

Stu Fox

[Richard M.]

Re: 1967 427 Holley 2300C Carburetor issue?

StuI can get the temp up to about 170 so I think I have a problem. See previous posts. Others having same issues.

I have to go out but will check back in late when I get back.

Thanks,
Rich

Rich;

Just a preliminary off the cuff comment; your concern may or may not be over blown (at this point in your assembly). I have often had AFB's do the same thing when sitting still idling, specially when engine is fully warmed. Wait until you have the car together and out running on the road under load before you conclude you have a big problem, or at least on a chassis Dino. Adjust it now as best you can.

I'll submit this as my initial impression until I have a chance to listen to your recording more carefully.

p.s. I noticed your center carb doesn't have an idle vent. Also, don't forget the end carbs also have a low speed idle function.

Stu Fox

[Ken A.]

Re: 1967 427 Holley 2300C Carburetor issue?

Rich, Wrong accel cam, wrong squirter, bad adj of acceler, idle too high, forget ported vac-go to full mech-38 deg @3000, richen idle circuit 2 drill sizes + 1 size on jets. Factory carb came too lean. A rich 427 is a happy 427. Make sure you adjust end carbs correctly!

[Richard M.]

Re: 1967 427 Holley 2300C Carburetor issue?

Rich, Wrong accel cam, wrong squirter, bad adj of acceler, idle too high, forget ported vac-go to full mech-38 deg @3000, richen idle circuit 2 drill sizes + 1 size on jets. Factory carb came too lean. A rich 427 is a happy 427. Make sure you adjust end carbs correctly!

Hmmm, sounds like you've been there Ken. Yes I was thinking the secondary carbs were in the picture but the linkage is well off the center carb's throttle lever end slot and the throttle plates seem shut perfectly. IIRC, before assembly, I used the opportunity to check throttle plates in the bores in all 3 for tightness.....I think. I have to take them off anyways now so I'll check again.

Accel Cam. This one is a green plastic cam, but I noticed it has 3 screw holes in the lever to attach it. Why is that? Could that be to move the cam for a "quicker" squirt? Unfamiliar territory for me.

Don't worry, full time vacuum will stay. Ported is not in this engines future.

These are service replacements and I may have a warranty claim ahead so I can't modify anything yet.

Thanks,
Rich

[Timothy B.]

Re: 1967 427 Holley 2300C Carburetor issue?

Hmmm, sounds like you've been there Ken. Yes I was thinking the secondary carbs were in the picture but the linkage is well off the center carb's throttle lever end slot and the throttle plates seem shut perfectly. IIRC, before assembly, I used the opportunity to check throttle plates in the bores in all 3 for tightness.....I think. I have to take them off anyways now so I'll check again.

Accel Cam. This one is a green plastic cam, but I noticed it has 3 screw holes in the lever to attach it. Why is that? Could that be to move the cam for a "quicker" squirt? Unfamiliar territory for me.

Don't worry, full time vacuum will stay. Ported is not in this engines future.

These are service replacements and I may have a warranty claim ahead so I can't modify anything yet.

Thanks,
Rich

Rich,

If you speed the motor with the idle speed screw will it increase RPM without bog down. If so, the problem has got to be in the acelerator pump circuit.

I have heard these Holley's can have debris inside from assembly. If you have it off the engine best to check that accelerator pump check ball like mentioned. You should get a shot of fuel with any movement but if it lags the engine will not catch up with all the air rushing in around the blades.

[Ken A.]

Re: 1967 427 Holley 2300C Carburetor issue?

Hmmm, sounds like you've been there Ken. Yes I was thinking the secondary carbs were in the picture but the linkage is well off the center carb's throttle lever end slot and the throttle plates seem shut perfectly. IIRC, before assembly, I used the opportunity to check throttle plates in the bores in all 3 for tightness.....I think. I have to take them off anyways now so I'll check again.

Accel Cam. This one is a green plastic cam, but I noticed it has 3 screw holes in the lever to attach it. Why is that? Could that be to move the cam for a "quicker" squirt? Unfamiliar territory for me. You want a red cam & use #2 hole

Don't worry, full time vacuum will stay. Ported is not in this engines future.NO VAC, convert to mech advance

These are service replacements and I may have a warranty claim ahead so I can't modify anything yet.I don't think Holley supports these carbs, since they don't sell them.

Thanks,
Rich

You can check for accel pump operation by removing the squirter. Don't lose the check ball!

[Richard M.]

Re: 1967 427 Holley 2300C Carburetor issue?

After a long diagnosis, I found the problem. (btw, I took a quick Holley course doing all of this. I think I passed)

I worked with the guys on the phone and I offered to help so we could get to the bottom of this asap. I pulled the center carb and removed the fuel bowl and metering block.


I found some debris inside the bowl and it was totally blocking one jet and other pieces left inside. The guys said it must have entered through the vent on top of the air horn and eventually lodged itself in there.

I also learned a bit about power valves. We suspected it may have blown since I had a few backfires when testing. I removed it and checked the diaphragm, seemed okay but hard to see deep inside. I made a MityVac hose contraption and tested it. It was fine.

The rest of it needs a thorough cleaning and air passages blown out. I'll re-check the accelerator pump and may go in for a closer look, but need to talk to the guys before I do.

I think it may be fine once it's thoroughly cleaned out. I'll probably open the other 2 carbs and check those for debris since I have them off. I suspect they may have similar packing debris inside and wouldn't know until they're activated under load.

The packing material in the box broke open in transit here and some of it must have dropped in the vents. I thought I cleaned it all out but never thought of the vents.

Stuff happens, could've been worse. Sometimes simple things just don't go right. If this all it turns out to be easy, I'll be a happier Holley'er.

Thanks for the help,
Rich
ps pics of the details here

http://s684.photobucket.com/user/richmz/library/Holley%20List%203660%20pics

[Donald A.]

Re: 1967 427 Holley 2300C Carburetor issue?

Rich, Wrong accel cam, wrong squirter, bad adj of acceler, idle too high, forget ported vac-go to full mech-38 deg @3000, richen idle circuit 2 drill sizes + 1 size on jets. Factory carb came too lean. A rich 427 is a happy 427. Make sure you adjust end carbs correctly!

[Richard M.]

Re: 1967 427 Holley 2300C Carburetor issue?

Don, I'm glad this helped. I learned much due to these problems. I consider myself a tad Holley smarter after this

One smoking gun was that the pump shot I was getting was caused by debris in the nozzle. Debris was green and I was confused. THen I took the accel pump apart and saw why. Green paint on the spring.

All the detail pics on PB. I cleaned repaired all three carbs today and just finished. I'll write something later to describe other things I found too. Dinner time!

http://s684.photobucket.com/user/richmz/library/Holley%20List%203660%20pics/Repair%20All%20Three

edit.....
While I had things apart I also experimented to learn more about the secondaries vacuum activation. I recall in some past threads someone, I think it was Duke, asked about what the vacuum spec was to open them during WOT. I used my MityVac and gauge to see what it took to move the diaphragms. It's hardly any vacuum. As soon as I applied the slightest amount at the pump, the diaphragm lever began to move. It is fully deployed at less than 1" Hg. You can see the tests on page three of the above link. A few here for future reference if PB goes south.
PA100056.jpgPA100058.jpgPA100059.jpg

The source for vacuum is a very small hole in the right throttle bore just under a cast line. After I tested the diaphragm on the bench after removal, I found the hole in the bore. Here....

Note this is bottom view. You cannot see the hole from top view.
PA100067.jpg


Rich

[Stuart F.]

Re: 1967 427 Holley 2300C Carburetor issue?

Rich;

I did my Mityvac test of the diaphragms with them mounted on the carbs and linkages connected and engine off.

Stu Fox

[Richard M.]

Re: 1967 427 Holley 2300C Carburetor issue?

Rich;

I did my Mityvac test of the diaphragms with them mounted on the carbs and linkages connected and engine off.

Stu Fox

Stu, Yes, after I found the hole for the vacuum source, on the other secondary I left it connected to the throttle shaft and blocked the hole with a piece of tape. Same results.

Did you have a vacuum gauge on it when testing? If so, what did you see when all-in? The diaphragms are very soft and must be designed to pull on minimal vacuum. These started pulling even before the gauge needle started to move.

Rich

[Stuart F.]

Re: 1967 427 Holley 2300C Carburetor issue?

Almost like we're talking apples and oranges. The system I'm familiar with was on my son's 69 L-89 (which should be the same, but not sure). Best for me to go back and watch your original test video to check your plumbing. It has been several months since I ran the tests on his, and it is not garaged close by for me to look at again.

Stu Fox