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Topic Review (Newest First)
08-22-2008 12:41 PM
reflog I've got a Street Avenger 600 CFM and I am currently running a 25 nozzle which gets no hesitation now that I have the accelerator pump set, the butterflies set, new fuel pump and the floats set. Timing was way off when I couldn't get the carb set. Mine is on a 327 SBC but if your engine isn't build up to severely I wouldn't think you would have to go higher than your 28 to get it to run correctly. This is just an opinion so take with a grain.

Steve
08-22-2008 11:25 AM
kleen56 I stand corrected, I checked the discharge nozzles on my carb and they are .28 in the primary and also.28 in the secondary. Holley recommends going to a .31 and .31 in the secondary if you have a hesitation on acceleration, which appears to be my case.
08-22-2008 10:50 AM
T-bucket23 At rest (idle) there should be no lash between the screw and the pump arm. At WOT you need to be able to move the arm an additional .015 to be sure you dont bend anything. There are several sites that have this procedure documented and have pictures.

Chet
08-22-2008 09:18 AM
kleen56
Quote:
Originally Posted by T-bucket23
25 is real small, most baseline at 28 or 33.
Also check your accelerator pump for zero lash

Chet
I've heard several ways of checking zero lash on the accelerator pump. I was told to WOT, then with a 1/4 in wrench push down on the accelerator pump arm, then measure the clearance between the arm and the linkage. That should be at .015 with a feeler gauge. Is this the right method, or is there a better one?
08-22-2008 09:11 AM
barnym17 Thats why I said ball park to get ya close,
08-22-2008 08:46 AM
T-bucket23 25 is real small, most baseline at 28 or 33.
Also check your accelerator pump for zero lash

Chet
08-22-2008 08:30 AM
Sixtyninemercury
Quote:
Originally Posted by barnym17
The best way I have found is to increase the size till it revs cleanly in nuetral or park then go up one size to get in the ball park. The reason for going up one is more load in gear requiring more shot.
All of my Holley's out-of-the-box have always rev'd no problem in neutral - but my built motor needed several sizes larger on the discharge nozzle. You can't estimate trying to rev it in neutral. Big difference between in neutral and taking off on the street!
08-22-2008 08:20 AM
kleen56 Thanks for the advice everyone. I tried to adjust the accelerator linkage again. Holley states it should be .015 clearance at WOT. I had slightly more than that and readjusted, but not sure if that amount would make a difference. I'll take it out today and see what happened. I'm running a 289, Mellings cam 480 lift 282 duration, 9.5 to 1 pistions, 351 W heads, Edelbrock intake, Sanderson headers to 2.5 pipes with Flowmasters. I don't know the weight of the vehicle but it's in a 56 Ford F100. I'm over 200, but on a diet. I saw an article on Ford Muscle, and they stated that the stock nozzles are worthless and 99% need to be changed. They recommended a good combination of 35 in primary and 35 secondary. I thought that was odd, but maybe they know something we don't? I know I need change the gears in the rear also. I'm running 2.75's for the highway cruise and have a C4 transmission. I've got a set of 3.50 which I use to have but highway was horrible. Use to tach at 3200 rpm at 60. May have to put them back in.
08-22-2008 08:01 AM
barnym17 The best way I have found is to increase the size till it revs cleanly in nuetral or park then go up one size to get in the ball park. The reason for going up one is more load in gear requiring more shot.
08-22-2008 07:50 AM
Sixtyninemercury
Quote:
Originally Posted by kleen56
I'm running a 4777 650 cfm Holley. The carb runs well, linkage adjusted correctly, jetting is fine. When I crack the throttle, I get a studder but then it clears. I was told to replace the discharge nozzles to correct this problem. I know I have 25 nozzles in the primary and 32 in the secondary. Any suggestions on which way to go as far as sizing? I've already dont the accelerator cam routine. Carb is running great except for the stumble when the throttle is cracked quickly.
As long as your fuel bowl levels are correctly set then you probably need to go with larger primary nozzles - 25's are tiny - probably only good for a very light car with a manual trans. Would also depend on how built your motor is and if manual/auto trans when sizing discharge nozzles to correct the off-idle stumble. On my 420HP-351W motor and C4 that's pushing a 3800# load down the road it needed 35 nozzles in the front. Tell us about your motor mods, trans and weight (including you in it, too).
08-22-2008 06:29 AM
reflog
Quote:
Originally Posted by kleen56
I'm running a 4777 650 cfm Holley. The carb runs well, linkage adjusted correctly, jetting is fine. When I crack the throttle, I get a studder but then it clears. I was told to replace the discharge nozzles to correct this problem. I know I have 25 nozzles in the primary and 32 in the secondary. Any suggestions on which way to go as far as sizing? I've already dont the accelerator cam routine. Carb is running great except for the stumble when the throttle is cracked quickly.
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

It is a studder or a small bog. Have you checked the accelerator pump adjustment? May be that you have just a little clearance and the shot from the accelerator pump is coming just a half second to late. Just a thought.

Steve
08-22-2008 12:30 AM
kleen56
Holley discharge nozzles

I'm running a 4777 650 cfm Holley. The carb runs well, linkage adjusted correctly, jetting is fine. When I crack the throttle, I get a studder but then it clears. I was told to replace the discharge nozzles to correct this problem. I know I have 25 nozzles in the primary and 32 in the secondary. Any suggestions on which way to go as far as sizing? I've already dont the accelerator cam routine. Carb is running great except for the stumble when the throttle is cracked quickly.

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