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Idle problem, transfer slots

Here comes an update.

I went down to about 0.015-0.02 inch on the secondary t-slots but it did not help, idle was to rich.
I removed the washers on secondary.

Now i have about 14 on idle and when tipping on the throttle it goes richer and not leaner, so tip in is gone atleast.

Went down to 77 jet on primary and 80 on secondary, running at 13-14 on cruise and 11.5-12 on WOT at 4000 RPM.
Today was a very hot day, so i will check AFR another day.

Idle to WOT in gear is still the big problem, big hesitation.

Fun thing is that for about a month ago i tried with the blue acclerator pump cam on the secondary and the car did hesitate ALOT, it almost died as soon as i hit secondary.
I thought i hade mounted the cam the wrong way so i turned it backwards and the hesitation was gone.
So when i mounted the accelearot pump cam backwards it was running ok on idle to WOT in gear.

After i changed the accelerator pump arm to a new as i bent the old not on purpose its not possible to mount the cam backwards as is pushes the pump all the way in directly and make the secondary stuck linkage to stuck.


Really dont know where to start on the accelerator pumps to be honest, as the AFR says its running lean but i already add very much fuel.

I have confirmed that its not caused by the temprature on the carb.
 
Have you thoroughly cleaned out the carb...blow through all the small passages? You shouldn't have to shim the throttle plates either.

Is this a new carb? Used?
 
BelvedereSatellite1966 said:
Thank you all again for the tips!



Very good information, thank you.
Do you have any article or more information on how to relocate the IFR?
Click to expand...


Hemming Muscle Machines mag had an article on the Holley IFR about 6 to 8 issues ago. I can dig it up and tell what month issue it was in if you want me too ? Ron
 
A/F gauges can be tricky. Especially at low rpm. Reversion,air leak can mess up the readings. A miss can show as lean. Remember its reading the oxygen,nothing else. I suggest reading the plugs. Can be subtle,do some research. But plugs dont lie. You can also look inside your headers for color at the flange. Another way that has been done is to drill a small hole in a tube or tubes right next to the exhaust port. And look at the color of the exhaust. Yellow is rich,blue is lean,white is real close to ideal. Do some research.
 
to me, it seems there is more than one problem with this carb. it is very possible in trying to fix one problem, more were created.

first off, to me, the 850 calibrations are too much for a 383 out of the box.
i personally have had best luck using the Pink cambers.

this is a pic of a 750 holley that i bought off a member here last November.
he said he was having trouble with it on his 383 BB. i am currently running this carb on a 302 ford, but i sent it to a carb tuner near me, and had the carb calibrations changed to work on the smaller engine, as you can see, it now has removable air bleeds for one, it also has smaller orifices in the metering blocks too.

you may have to do this to get the performance you want.

20160203_171912_resized.jpg
 
Thank you all for the answers again, i'm very happy for all the answers.



Bigal75 said:
Have you thoroughly cleaned out the carb...blow through all the small passages? You shouldn't have to shim the throttle plates either.

Is this a new carb? Used?
Click to expand...

I have cleaned it out with air compressor, every single passage.
It's a used carb, don't know how old as it came with the car.


383man said:
Hemming Muscle Machines mag had an article on the Holley IFR about 6 to 8 issues ago. I can dig it up and tell what month issue it was in if you want me too ? Ron
Click to expand...

I can dig it up by my own, thank you for this tip!


hangn0ut said:
A/F gauges can be tricky. Especially at low rpm. Reversion,air leak can mess up the readings. A miss can show as lean. Remember its reading the oxygen,nothing else. I suggest reading the plugs. Can be subtle,do some research. But plugs dont lie. You can also look inside your headers for color at the flange. Another way that has been done is to drill a small hole in a tube or tubes right next to the exhaust port. And look at the color of the exhaust. Yellow is rich,blue is lean,white is real close to ideal. Do some research.
Click to expand...

Checked sparkplugs, looks good, it seems to be relevant what the AFR-meter gives me.


mentor70 said:
to me, it seems there is more than one problem with this carb. it is very possible in trying to fix one problem, more were created.

first off, to me, the 850 calibrations are too much for a 383 out of the box.
i personally have had best luck using the Pink cambers.

this is a pic of a 750 holley that i bought off a member here last November.
he said he was having trouble with it on his 383 BB. i am currently running this carb on a 302 ford, but i sent it to a carb tuner near me, and had the carb calibrations changed to work on the smaller engine, as you can see, it now has removable air bleeds for one, it also has smaller orifices in the metering blocks too.

you may have to do this to get the performance you want.

View attachment 352773
Click to expand...

Yes, i think 850 is to big for my engine to, but i will give it a little more of try before i switch to a 750.
 
So i tried with some different cams, no real difference.
Now when to winter almost is here in Sweden and the temrapture is lower i can feel i hesitation when opening secondarys cruising.

Changed my squirters from 35(prim)40(sec) to 31(prim)35(sec), when not opening the secondaries i can only say WOW what a kick in the ***, runs perfect on only the primaries.
The secondaries are still the problem, it runs best on 35 squirter on sec. 31 and 40 on secondary gives the same amount of hesitation.
My teory is that 31 gives to little fuel by the dimension on the squirt, the 40 gives more amount of fuel but to slow as i see its do not have the same kind of jet more like a stream.

I think i need to expose my t-slot on secondary as there is a bog when just cranking the secondaries, its the same problem i had on the primaries before, but worse on the secondaries.
Hitting zero to WOT will make the car cough, cough, cough, die for a second and then take off!

The reason why i today not have the t-slot exposed on the secondaries is that i get to rich mixture with only a hair of the t-slot exposed.
Mixture-screws about one turn out will give AFR on idle at about 11:1, turning them in all the way will make the RPM rush and give me the slow idle-return(is this what they call idling on transfer slots?).

If i add more air to lean ot the idle my RPM will be to high.

If i add i little thread to the IFR, will it bring my AFR down or will it just have the same effect as turning the mixture-screws to the bottom and make it "idle on transfer slots"?
If i add a thread to the IFR as in the attached picture(i will use a smaller thread), should i add it on all four IFR's, the two on primary and the two on secondary?

Here is a album, can you see something wrong with the meterblocks/body and the gasket?


I attached pictures on the blades, the one with the bushings is the primaries.

Is my pump to small on secondary as it lacks the power on the jet with 40 squirt, do i need to up on the squriter and pump to get a bigger and stronger squirt?


I'm really close to buy a Summit 4010 750 DP as i can get it for 300$.

ifr.jpg Primaries.jpg Secondaries.jpg

PS. Had a backfire through the carb when i standed with my head above the carb today. I can cancel my apointment at the barber....
 
Last edited:
I know I have a completely different set up however I have a 572 ci with a 1050 dominator and only run 26 or 27 for squirters.
 
If you return your carb to original. Set the primary throttle blades to expose the transfer slot so it looks like a little square. Set the idle afr with your wideband to 13 or so. Try 31 or 35 squirters.
 
Bigal75 said:
If you return your carb to original. Set the primary throttle blades to expose the transfer slot so it looks like a little square. Set the idle afr with your wideband to 13 or so. Try 31 or 35 squirters.
Click to expand...

I can do that, but then i will need to go down on initial from 15 degrees to 5-7 to bring the idle down, exposing the t-slot without my bushings will give me more air and to compensate i will need more gasoline on idle=higher rpm.
Thats where i started.
 
Have you tried shutting the primaries until it idles lower? Have you tried driving it like that?
 
Bigal75 said:
A dominator only has a white cam I think. Personally I don't think that's your issue. There may be an issue with the carb. I would try to get acceptable afrs first at idle and part throttle then work on the pump.
Click to expand...
The afr on idle and Cruise is perfect now. 14,5-14,7 on cruise and idle and 12,5-12.8 at wot after the engine picks up.
This is with only exposing t-slot on primary and with my bushings on primary.
I have a tip-in problem on the secondaries and hesitation on wot.
Thats my why i have the idea to expose t-slot on secondary.
Maybe exposing t-slot on secondary is not needed with a right sized carb, but it maybe need that as my carb is oversized?
 
The transfer slot transitions from idle circuit to the mains... it really only applies to the primaries since when you're cruising you often transition back and forth from the idle and main circuit.
 
I had a 4160 750 vacuum secondaries that did the same thing on an old Chev truck. Got rid of it lol. Seriously, perhaps there isn't enough signal? I would try another carb if you can get a buddy to lend you one.
Did you buy a cam kit for the carb? If so did you try them all?
 
850 dp is not to big. When I was in high school my friend had one on his 68 roadrunner. Ran fine. Seemed like every big block had a 850 dp.
Stumbles when the secondaries open. What does your gauge say when this happens? With a big cam and big shooters you might be using up the shot to quick. Smaller shooters lenghten the duration of the shot. That spring on the linkage can compress and then extend keeping the shot going after the pedal reaches wot. Have you looked at your gauge while its stumbling? What color is the exhaust when it stumbles? Rich or lean can cause a stumble. A combination of both can cause a stumble too. Big shooters and not enough duration.
Your actually doing pretty good for having no experiance with carbs. But I think you can benefit from some good reference books. SA design publications has some good ones. Supertuning holley carbs by David Vizard is a good book. How to make horsepower by David Vizard is another one. Reasonably priced and easy to get. Try em.
 
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