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Author
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Topic: Carb problem
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65driver
Gearhead Posts: 209
From: Syracuse, NY
Registered: Feb 2000
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posted 04-29-2004 09:54 PM
   
I just got the car back on the road and need to deal with a carb problem from last year. I have a major stall/flat spot off idle when I mash the gas. Car is a 65 fb, 289, 270H cam, e-brock heads and rpm intake, headers, 2400 stall C4, 3:50 gears, 600 vac sec Holley. Same thing happens when rolling about 15 mph or slower. If I bring the revs up to about 1000 or higher, then mash it, its fine. The carb is box stock. I want to get back to the track, but would like to solve this problem first. I ran a best of 13.97 on street tires, and want to be in the 13s all the time. Where do I start with the carb problem?
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Fastymz
Moderator Posts: 20638
From: Reno Nv USA M&M#1240
Registered: Apr 2001
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posted 04-29-2004 09:56 PM
Try going to a bigger squirter. ------------------
SCOOP oddly obsessed with big scoops on little Mustangs 65 coupe,351w,C4,Big Boss 429 hood scoop,8" 3.40 TracLoc. My Pics [This message has been edited by Fastymz (edited 04-29-2004).]
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Dynoram
Journeyman Posts: 51
From: ford country
Registered: May 2003
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posted 04-29-2004 10:05 PM
try moving the accelerator pump cam foward so it activates earlier.
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steve'66
Gearhead Posts: 9476
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 04-29-2004 10:38 PM
Bigger squirter, and maybe different accelerator pump cams. Also could be that the secondaries are opening too fast, but unlikely with a 289/302. You need the lightest yellow spring in the secondary.  SteveW
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wildfire466
unregistered
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posted 04-30-2004 01:04 AM
Re:65driverCan of worms my friend. In order to correctly help you must provide some more info. 1. You installed the engine and had no problems
2. You added X and now you are experiencing problems There is a whole bunch of things, so I'll tell you without proper knowledge of your set-up. a. Vales set too tight
b. Vac Advance inop
c. Cold plugs or wrong gap
d. Vac leak at intake or base of carb
e. Incorrect accel spring adjustment, um .015 gap at Full throttle.
f. Low fuel pressure or water in fuel.
g. Cracked fuel line at gas tank causing air to enter the system. Check off the list and post what you find? Les ------------------
http://www.geocities.com/wildfire1mustang/ [This message has been edited by wildfire466 (edited 04-30-2004).] [This message has been edited by wildfire466 (edited 04-30-2004).]
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65driver
Gearhead Posts: 209
From: Syracuse, NY
Registered: Feb 2000
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posted 04-30-2004 06:43 PM
Answers:
Changed from Edelbrock Carb - no flat spot,before change. a. Valves are right on the money
b. Vac Advance locked out, running only mech.
c. Plugs are ok, didn't change
d. No vacuum leaks anywhere
e. All adjustments on carb look ok
f. New fuel pump last year, still ok
g. All fuel lines fine, fresh gas, no water in it. How Can I check what squirter is in it now?
How do I know what accelerator pump cam is in it?
Should I change the cam first, or go to a bigger squirter?
What size squirter? SteveW - Do you mean the spring inside the diaphram?
Thanks for the answers - this is driving me crazy.
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steve'66
Gearhead Posts: 9476
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 04-30-2004 07:02 PM
A box stock 600 Vac Holley will have too stiff a secondary spring in it. You'll need the spring kit and then you'll need the lightest one in the kit for the little 289.That said, that isn't causing your problem, it just isn't opening the secondaries. You current problem is probably too small a squirter. The squirter is what the gas quirts out of from the accelerator pump, also known as pump discharge nozzles. It's probably a 28 or 29 now. One large phillips screwdriver will remove it, the number will be stamped into the side of it. Try a 35 and let us know how that works. Then change the secondary spring and see if you can get all 4 barrels to open under load. (they won't open sitting in the driveway) Have fun! SteveW
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steve'66
Gearhead Posts: 9476
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 04-30-2004 07:03 PM
quote:
Originally posted by 65driver:
SteveW - Do you mean the spring inside the diaphram?
Thanks for the answers - this is driving me crazy.
Yes,
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65driver
Gearhead Posts: 209
From: Syracuse, NY
Registered: Feb 2000
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posted 04-30-2004 11:24 PM
SteveW - thanks for the recommendation. I'll see if the local speed shop has what I need. After I get some changes made, I'll post again. Thanks again.
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Stang72
Gearhead Posts: 280
From: Arkel,Zuid-Holland,Holland
Registered: Jan 2003
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posted 05-01-2004 02:45 AM
if nothing helps, open up the Holley,...i had similar problems, until i opened it and found lot's of casting residu /drilling curls (no kiddings, some were 2"long!!!) and other sort of left overs...... clean it, adjusted the setting (which i got here  ) and started rippin'up the street!! i got an answer back from Holley ,they had more cases with this kind of problems so they know about it... good luck Ben
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ted
Journeyman Posts: 75
From: Central Texas
Registered: May 2003
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posted 05-01-2004 10:05 AM
Before opening up your Holley, check both the primary and secondary float levels. If either is low, then a flat spot or hesitation due to late pullover of fuel into the main circuit can occur. Secondary float level is important and is a significant player with low rpm performance. Bare minimum is having the fuel level at the bottom of the sight openings but slightly higher can help at times. A pair of clear sight plugs ($4 a pair from Mr. Gasket) can allow you to accurately set the fuel levels at something higher than just the bottom of the threads.Also check that the accelerator pump linkage is set correctly. Any air gap in the linkage at idle will invariably promote some hesitation upon acceleration. With the throttle in the wide open position, the accelerator pump diaphragm should be within 0.020" of bottoming out and at the idle position, there should be a given amount of preload on the linkage. ------------------
Ted E.
Fe's are plenty fast, but "Y"'s are fun when they run in the nines.
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cracing
Gearhead Posts: 428
From: Saltillo Miss. USA
Registered: Jan 2002
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posted 05-01-2004 02:23 PM
As others have said could be many things. first adjust pump linkage to where you can just touch throttle & gas will squirt from shooter nozzles,an instantanious strong shot is required. Spring screw should just touch pump arm with no pressure on arm. I have found that if you install pump cams upside down (flat side up) it will give an instant shot for that super quick foot action.LOL Too lean on idle mixture will also cause a flat spot off idle.Make sure sec plates are closed, if not there is a small screw on pass side of baseplate accessible from bottom side only to adjust it.Make sure pri throttle plates are not opened too far that they pass fuel transfer slots in throttle body. You can adj sec. to compensate for this. Then if all that fails increase shooter size. Finally where is your initial timing at? Retarded timing will give those symptoms as will a carb that is simply too big for application. Hope I havnt confused you too bad.
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65driver
Gearhead Posts: 209
From: Syracuse, NY
Registered: Feb 2000
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posted 05-03-2004 06:20 PM
OK guys, I'm ordering some stuff and need some help. I'm ordering clear site plugs, new 35 squirter and some vacuum secondary springs. What kind of squirters - there are straight type and tube type? Also, should I get the quick change kit for the secondary springs? Also, should I get the pump cam kit as well? Its been just about 20 years since I had a Holley apart, so can antbody recommend a book to help me with the parts change, or can some one here give me a step by step?Many thanks for the advice. Its been awhile since I got into tuning for some bracket stuff. Chris
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Fastymz
Moderator Posts: 20638
From: Reno Nv USA M&M#1240
Registered: Apr 2001
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posted 05-04-2004 01:47 AM
The holley catalog as lots of good info,and this book helped me a lot. Holley Rebuilding & Modifying by Jeff Williams from SA DESIGN. I have the quick change kit for secondarys. It comes with a spring kit. I also got the cam kit not sure I'll ever use them all. But I have them now. I was told it didn't make a difference on the squirters. ------------------
SCOOP oddly obsessed with big scoops on little Mustangs 65 coupe,351w,C4,Big Boss 429 hood scoop,8" 3.40 TracLoc. My Pics
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65driver
Gearhead Posts: 209
From: Syracuse, NY
Registered: Feb 2000
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posted 05-13-2004 09:23 PM
Just an update:
-Changed the squirter to a 35
-Installed a quick change kit, and put in a long yello spring.
-put in clear site plugs and re-adjusted the floats.No flat spot, goes like stink when you mash it! Thanks for the advice. Hopefully there will be a test and tune this weekend. Is there an easy way to change the squirter with the carb on the car? Thanks again Chris
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V8 Thumper
Gearhead Posts: 4638
From: Phoenix, Arizona
Registered: Dec 2001
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posted 05-15-2004 08:07 AM
quote:
Originally posted by 65driver:
Is there an easy way to change the squirter with the carb on the car?
Sure. Just use a long #3 phillips screwdriver with a dab of grease on the tip so the screw will stick to it. It is much more difficult on an airhorn that still has the choke mechanisim in place. In fact, when I still had the choke on my car, I'd pull the carb to do shooter swaps. If you drop something, you'll need to remove the carb and pray that you don't bump the throttle shaft as whatever part(s) you dropped are sitting on top of the closed butterflies 
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1965 GT coupe, 333ci aluminum headed/solid cammed stroker, four speed, 3.70:1 9" All Blue Oval, no blue bottle
http://mustangsandmore.50megs.com/V8Thumper.html
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