Carter AFB 9636 ?

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66dartgt

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Anyone know what the float settings are for one of these carbs ?

Edelbrock says their afbs are supposed to be 7/16", my carter carbs book doesnt specify the 9636, but says the 9000 series is supposed to be 9/32". Thats alot of difference. My old mopar service manuals talk about 5/16". I dont have the spec sheet for this model carb so some assistance is appreciated.

Thanks !
 
I just purchased and installed a rebuild kit for this exact carb. According to the instructions that came in the box, the float settings are;

Float level; 5/16, float level with gasket inplace on inverted top.

Float drop; 15/16 with bowl cover held upright and gasket inplace.

Measurements are at the float ends. (Tips)

Some of those measurements seem to be for the needel and seat clearance and a slightly diffenet setting on float height and drop without the gasket inplacxe. Edelbrock may run a slightly richer setting on the floats.

I don't know what that 9/32 is for. Thats not alot of space.
 
Excellent, many thanks - will use your data in setting mine. My carb kit came without the settings or the assembly sheet. Ebay special LOL.

What jets and metering rods are you using ??

Thanks again !
 
Currently, it is OOTB stock. What engine are you useing it on and what mods?

You should have a rod and jet kit for this. I don't know if the Carter kits are still available. But there very good kits unlike the Edelbrock kits which do not have many parts in them. They should have enuff to tune the carb, but the Carter kits have alot of rods and jets.

I will be setting this carb up later, for the spring(ish) time. It's part of a general test between that and a OE 340 AVS and a 1460 Holley. The Holley is modified with a 4150 kit. The kit does away with the rear metering plate in favor of a 4150 style metering block to make easier jet changes as the OE design is a metering plate.
 
Hey Rumble thanks for replying, maybe we can put our heads together and figure out wth is wrong with this carb.

Basic engine set up -

just started up fresh rebuilt 318 bored 60, mopar 268/272 455 lift cam, CR is 9:1, 302 heads with 1.88/1.60's, bowl ported and intake runners opened up. Cam was broken in at 2500 rpm for 20 minutes.

Engine starts and runs but idle is horrible, I can see droplets of gas coming out of the main discharges on the primary booster venturies. Obviously the idle mixture screws dont do jack. So I tore it apart and did the following based on your info today:

I reset the floats to a hair over 5/16, about 11/32, float drop set to 15/16.

Flushed the emulsification tubes for the primaries and secondaries, flushed out the idle mixture passages etc. Checked for dirt on the needles - nothing, all looks fine.

I have an edelbrock strip kit with the rods and jets etc for their version of this carb.

Jets - .098 primary, 7347 rods, .095 secondary jets. Lowest vacuum rating step up spring 3 in hg.

I still cant get the idle mix screws to do anything and the fuel droplets are still coming out of the main discharge on the booster venturies.

I figure the following needs to be checked:

Fuel pressure should be 5-7 psi

Buy another carb kit and check the contents to see if something is wrong with the gaskets in the carb now.

If that doesnt check, then tear the carb down again and set the floats lower to Edelbrocks settings, and check the floats for leakage. I did that once before but maybe they got messed up. Flush the emulsification tubes and the idle mix screw holes again.

Anything you can think of I am missing ? I'm starting to grasp at straws on this thing.
 
I think taking the boosters out and making sure they are clean and clear of debrise is a good direction.
(You know this is an emissions calibrated carb right?)

Different float hieghts can help, but I don't think that'll do it. If the idle screws don't do jack, your to rich. 2 - 2-1/2 turns to the left is a good starting point to see where your at with the idle.
Whats the idle rpm?

I'm running out of time..I work midnights and it's close to leaving time.
ttyl, tomorrow...
 
Rumble -

After sleeping and thinking on it - this is a used carb that I bought at a swap meet, who knows whats been done or changed in it. I have a set of floats from an ancient afb in the garage, the floats that came with and are in the 9636 carb IIRC looked much smaller.

I am beginning to think that the floats in the carb might be the edelbrock pieces, if that's the case, then it should have some kind of effect on the actual gas level in the carb, meaning that maybe the edelbrock floats require a much larger closed setting dimensionally speaking. Im gonna check that out first.

I'll do a volume displacement in water measurement and see how much difference there is in these two sets of floats.

Im not worried about the calibration for emissions as long as I can get this thing to run correctly, which it is far from at this point.

Wish me luck - will keep you posted.
 
OK, sounds good so far. Your strating with the floats, moving onto the possible cloging passages in the boosters and then leaning out the carb.

Try a 75** rod. Thats about the thickest in there right? If it needs to be leaner, you'll probably have to rejet.

.098 jet minus a 73 rod = 25 A 75 makes clearance 23. Hummmmmmm, thats kind of on the lean side I would think. Hummmmmmmmmmmmmmm
 
Rumble - Sorry for the delay in posting.

I'm on to something here I think. yesterday I checked the fuel pressure and its about 6.5psi. If my guage happened to read slightly off this reading could be over 7 psi or something less than 6.5 psi easily. I am leaning towards it reading low and the actual value is high. Why else would the thing be flooding. Edelbrock says over 6 psi pressure should use a regulator.

So, I reset the floats to the 7/16 setting per edelbrock, flushed the idle and emulsification tubes again, reassembled it and ran it.

Better this time - now instead of both primary boosters dripping fuel, the passenger side is dripping and the drivers side is not. The idle mixture screws are gaining some sensitivity. Not completely because the booster as I said is dripping still on one side.

If I am interpreting this correctly, the fuel pressure is too high. I bought a regulator and will slap that in today and see what happens. wish me luck.
 
High fuel pressure can cause trouble, especially if somebody has put larger needles/seats in the float valves. Also, make sure the floats are shutting the fuel off.

How far are the primaries open? Your combo sounds pretty mild (like a stock carb should work OOTB). But, if the primary throttle blades are open far enough to uncover the transfer port, your main circuit might be coming into play.

Other check, make sure the rods are going down all the way at idle. Remove their little covers, start the engine and they should "suck down" right away, and at the same time. If the rods are up at idle, you will be stupid rich.

Two things to try, but try them one at a time independently. Go down one jet size (if you use Edddy jets they have a different numbering system) and see what happens. Keep same rod.

Lower the float another 1/8.

Either one will lean you out across the board.
 
Good thinking Cheif.

If the needle and seat are oversized, they will be hard to seal and will need a different float setting, lower, so it will give more pressure to the needle to seal in the seat.

Fuel pressure is also a good idea to look at. It will act just like what Cheif was saying about an oversized needle and seat.

Ohh, the joys of carb tuning...He he he, step by step......
 
Finally back at it - Took turkey day off and had to fix the garage furnace yesterday, and started installing the regulator.

The other day when I reset the floats to 7/16" I pulled the booster venturies out and cleaned them , ran a small copper strand of wire thru all the passages in them, and flushed again with carb cleaner. So Im pretty sure the passages in those things are clean, I also blasted out the idle mixture passages and transfer slots. Clear -

Finished installing the regulator this AM set the pressure for 5 psi - checked it for the dripping - still doing it. As I had mentioned, the passenger side booster venturi is dripping gas out of the thing, drivers side looks okay.

So, I pulled the carb top off again and inspected the needles and seats once more. It all looks fine - I examined the seats with a magnifying glass as well and saw nothing to be concerned about. I happened to have some new needles of the same length but with a larger diameter rubber tip on them. Stuck them in checked the float level and tested it - no joy, still dripping.

Checked the step up pistons with it running and they slammed down tight and not fluttering. In addition I did install the smaller jets I had from .100 to .098 and went with the leanest rod I had - a 7347. Along with the weakest step spring set I have -

I'm beginning to think there is a design issue with this carb or something, maybe a bad casting or a problem with the passenger side booster venturi. Maybe thats why it was a swap meet item, although I see nothing to be concerned about with it in general, it was well cared for and pretty clean when I bought it.

I'll take your advice chief and try setting the passenger side float another 1/8" lower and see what happens. It cant be anyworse than it is now.


If that does not fix it - Im buying a new carb - Ive spent enough time trying to figure this damned thing out.

I can pick up a new eddy at CSK or somewhere else, and end my misery. Assuming its the carb and somesort of inherent flaw in this used one.
 
I will try resettting the float tonite.

I have one other thought. If the throttle is partly open then it would tend to make the main circuit start working, which Chief mentions. I remember on another carb, different motor with a big cam, I had to drill some small holes in the primary butterflies to make the idle circuit work. That maybe another approach. lets see.
 
Do you have a big(ish) cam for the street? Low vacuum? Tight centerline cam?

Then that may be needed.

Do you have spare butterly plates? Incase of mistake. You can't put back what you drill out.
 
AHA !!

I set the passenger side float lower by 1/8 inch, and retested. It was still dripping on the pass. booster. After I got the motor warmed up, I slowed the engine down until i didnt see the booster dripping - bingo - the butterflies are open too much for the idle circuit to work, and it's pulling over the booster(s). Once I got it slowed down, i was able to adjust the idle quality by messing with the mixture screws. Damned thing. The weird thing was the idle before I reset it, was not that much faster, maybe only 850-900 rpm.

So I have finally gotten it to work and now understand what it's doing. Idle vacuum at about 750rpm is 9.5 inches. Timing is set at 10 btdc.

I am going to try and run more initial timing, to get the vacuum up and smoothed out. I realize I will have to mess with the mechanical advance slots if I run more initial. Im not running vacuum advance, and have one light mr gasket spring and the lighter of the two stock springs in the dizzy.

After that and only if needed - will try drilling some small holes in the primary butterflies. I read in a book for holleys that suggested starting with 1/16" holes in each butterfly - test, and then go from there, when dealing with a lumpy cam.

I probably wont get far with it tomorrow other than setting the timing up higher, maybe 15 btdc or so. I am going on an overseas business trip on Monday. It'll be 1-2 weeks before I screw with it more.

The cam I put in the motor is the mp 268/272 .455 lift - specs are 110 centerline 50 degrees overlap. When I called mopar they told me the duration is 228/232 at 50, so in my opinion this is not a monster cam. I would expect more vacuum/carb problems with a higher overlap - something closer to 60 degrees - this is in a 060 over 318 with 9:1 compression. I checked and verified the centerline when I installed it - straight up at 110.

Well, at least I finally have some ideas about my next steps. If you guys have some other suggestions please feel free to make them. I appreciate your thoughts, and assistance.
 
Goooood. Your on your way.
The purple cam isn't to big. It should be a nice performer in there. Whne you start to advance your timing some again, you'll need to close down the idle screw for less of an opening again. The fuel coming out is called pull over I believe.

Have a good trip, ttyl after you get back.
 
Don't forget to put your floats back to a sane setting, and perhaps up-jet slightly. The 1/16" holes will help you out if you need to re-establish proper throttle blade angle at idle.

So why aren't you running vacuum advance? You hate gas mileage or something?
 
Im not running vac advance because its easier to start with none anyway and then work towards getting it operational.

I still dont see why this set up pulling such lousy vacuum, 9.5" at 750 rpm. Before I left on this trip I reset the timing to 15 degree btdc, and the vac didnt really improve. When I bumped it to 25 btdc (ridiculous of course) the vac picked up nicely. Im beginning to think i screwed up setting the centerline on this thing. Any easy way to check the CL on a cam installed in the motor ?? Maybe a tight fitting dowel thru the pushrod hole in the head sitting on #1 intake lifter and a dial indicator on top of it to read the lift vs degrees measurement ??

Oh well, might as well go drink some beer (in germany right now). TTUL
 
Well - I think I have convinced myself I did not centerline the cam properly. I have checked for vacuum leaks on the intake and carb base using carb cleaner and saw no change in idle or engine speed, 9.5 inches is it. There are no other vacuum anythings on this car, other than the pcv which is working correctly.

A buddy used the same cam in a similar 318 and he is pulling 13-14 inches at idle. Several other things I noted. Engine seems to run what I would call heavy (for lack of a better term). It spits out the carb a little and gives a mild backfire once in while when its revved.

Oh well, you'd think I'd know what I was doing after having built at least 30 or more engines with friends, or on my own, and half of them small block mopars. Ive got all winter to screw with it.
 
Ive got all winter to screw with it.
Click to expand...
LOL, that's how I feel about it all. Better yet for me, the wife gave me an early Christmas present, a LP gas heater for the garage. 125,000 btu.

Carb sounds lean if it is back fireing. Otherwise, your right, timing.
 
Heat = Good !

I need to move the car from the unheated side of the garage to the heated side to continue working. It was 5 degrees here the other day - too damned cold to work on it. We've also got 6 inches of snow on the unpaved grass going to the heated garage. Well, it'll sit until this mess melts off, or I run the snow blower around on the grass, if I get impatient, or it remains too cold. Sooner or later !!
 
66dartgt said:
Im not running vac advance because its easier to start with none anyway and then work towards getting it operational.

I still dont see why this set up pulling such lousy vacuum, 9.5" at 750 rpm. Before I left on this trip I reset the timing to 15 degree btdc, and the vac didnt really improve. When I bumped it to 25 btdc (ridiculous of course) the vac picked up nicely. Im beginning to think i screwed up setting the centerline on this thing. Any easy way to check the CL on a cam installed in the motor ?? Maybe a tight fitting dowel thru the pushrod hole in the head sitting on #1 intake lifter and a dial indicator on top of it to read the lift vs degrees measurement ??

Oh well, might as well go drink some beer (in germany right now). TTUL
Click to expand...


How could you mess up the C/L installing the cam ? Only way I see is if you are 1 tooth off on the timing chain. I seen a motor that jump the chain 1 tooth before on a very old chain, motor did run but was very weak, at all speeds.

You should try to take the spark plug out and turn the motor by hand untill the #1 piston is at TDC. You could try to look to see the piston top with a flashlight or stick your baby finger in the hole to feel the piston--don't get it stuck thou-- Move the crank back and forth and try to see if the piston is at TDC. Once it is, look at the timing mark, it should be right at -0-. This way you know if it times at 25 btdc it really is @ 25 btdc, not 10-15. Once in a while the timing marks slip on the balancer.

Did you look at the dist. and make sure the advance is working, sometimes it freezes up because of rust, doesn't take much. The rotor should move 1 way and snap back when let go.

I would check both before checking the timing chain. Taking the cover off is alot of work. You must have line the dots up right, I mean its not that hard to do, unless your eyes are bad.

You did use a good timing chain set, right ? Not some E-bay special made in China with maybe miss match parts.
 
dodge freak - Yeah - before I tear it down I am going to check TDC using a positive stop installed in the #1 spark plug hole. If it checks correctly I plan on getting an extension for my dial indicator and put it down thru the #1 intake pushrod hole and check the centerline that way, no major tear down required to do this - just pull the plugs, radiator, and the valve covers release the valve train and do it.

Timing chain was a new cloyes tru roller set - I doubt there was a problem with it, but anythings possible.
 
No, your timing chain is fine.

The only neg. that I have hear about Mopar camshafts-and I just hear this, don't know if its true--is that some are way off and its best to degree those cams. Seems unlikely but I do recall reading it believe on dodgecharger forum a year or 2 ago. I did not agree with all the advice on there, thou.

I have found you can time the motor by ear. Unhook the vacuum advance if you have it, believe not. Rev the motor up until all the advance is out. Ear muffs are a great idea and while reving it 3000-4000 rpms, turn the dist until the motor stops speeding up or starts to get a little rough. Then back it off a bit. That should get you like 35 degress total.

That be faster than checking everything, thats how I time my motor, I still do look after with a timing light but its always right around 35. If you do time it that way, then slow it down to idle and see how much vacuum it has. If its still low....well IDK, you got a vacuum leak or the cam is way off.
 
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