Hay guys new to this type messaging but not Fords and these carbs. I do have a problem with a simple flat top 4100 that wont settle down and idle. It has no vacume leaks has been thououghly cleaned and runs great other than idle. It is on a mild 289 with a Cobra intake and fresh motor. The air bleeds don't respond to adjustment and when I look down thru the primary side I see fuel dribbling into the carb from the booster venturies assemblies. I don't recall this being the normal way the carb operates in the lower rpm/load mode. I put this carb on because I got tired of the holley headaches. Any help would be greatly appreciated.

Don

Have you checked the power valve and/or it's gasket?

I thoroughly Rechecked the power valve and it has no hole and holds "air". The gasket seems fine and I rechecked the passages for bolckage, all seems fine. I suck on the power valve and it moves correctly nad has no hole. Could I have the wrong base gasket on it. It is the four hole that covers all the base but the actual venturies. Do you have any other suggestions. It still dribbles out of the booster ports on the primary side. It will not respond to air screw adjustments.

Thanks Don

and weight under the booster hold-down screw. The manual says to "seat" the ball with a tap from a hammer and drift. If you don't have a good seal there, fuel will be sucked into the engine through the accelerator system.

I have had several power valves that looked good, but are not.

Now I have a power valve tester to test them.

Power valves are cheap, Holley power valves fit the 4100 . I belive that the stock power valves for 4100's are 6.5-7 hg.

Ed Jenkins

Ford Galaxie Club of America member #3350
1966 Galaxie 500 Convertible built in Chicago Illinois, will have a stroker 390( 429 cid?). 780 Holley?, built C6, Crites Aluminum radiator, and a rust free frame from the south. Work continues.

Please visit and revisit the Carb Forum athttp://network54.com/forum/88781

First it does sound like you have a powervalve that is blown and/or bypassing fuel, that is what is causing SOME of your fuel dribbling.
Secondly and YOUR BIGGEST PROBLEM, you have the improper carb for your engine, You have a 1966 GALAXIE FE carb for a 390 and you have it installed on your 289 so that is why you are having a problem getting it dialed in, My bet is you got it all rebuilt and it doesn't run right and now you are trying to tweak it to get it to idle and prevent stumbles and settle down.

Bill White
White Automotive

In reading the many pages of carb information on this site and reading your response I am beginning to think this carburator is unusable on the 289. I originally had a 600 Holly on the engine and it ran quite well except it constantly had the usual leaking issues and related Holly problems. I was thinking this 600 flat top would be a nice replacement and of course might need jetting and some misc tuning but would be functional once sorted out. Can I make it work? I also have a new factory fuel pump with filter canister that seems to put out a lot of pressure, could this be contributing to the problem? Would it need to be regulated (I never had to before) it seems to hold pressure and the float level is not too high.

Finally, I also have a very nice 6CAF-F 1.08 carb. Should I scrap this 600 and work on the 1.08 carb for better reliability and drivability?

Thanks for your great help...D.C.

That C6AF-F is also a california emmissions carb for a FE powered Galaxie.
Ideally you are looking for a 1.08 carb that has a Z,O or G code rather than the A code in the part number. A is for galaxie and S is for Thunderbird, You will want to stay away from any of those Especially a 1966 1.08 which are often passed off as a small block carb but of course FORD NEVER made a small block 4 barrel for the galaxie or thunderbird, Those 66 1.08 A and S codes are all california emmission carbs. And as you know the only one after that to really watch out for (and there are a TON of them out there)are the 66 P code wich is the factory replacemnt for ALL 4100's from 1966 thru the late 70's but it was based on the 66 fairlane 390 GT california emmission carb.

As far as making these two work, you are really facing an uphill battle, to be honest I get calls on this situation almot regularly. These california emmission carb are intended to run with the FE engine which makes your engine about 100 cubes less and totally different fuel profile. quite frankly these didn;t even run that well on the FE engines. Most people really mess up and when rebuilding it bench set it to the mustang specs when it should be speced to the carburetor, then it doens;t run correctly so they start changing things and number 1 most people change is the jetting which now has really screwed up the carburetor, then they play with the idle mixtures and choke till by the time they call me its really a messed up puppy.

Best advice I can tell you is find a comparable carb that will work for your situation as described above, In the meantime or if you just have to run this carb, make sure the bench settings are set for the proper vehicle, so for the P carb that would be the 1966 Fairlane GT 390 for the A carb that would be the 66 Galaxie 352/390, that will at least get the carburetor properly set-up, OF course it goes without saying since this application is not going to be compatible then EVERYTHING else must be in good shape, so that carburetor if its dirty or needs a rebuild NOW is the time to do it.
Once set up good, now you can run it and see how that jetting is going to work with your vehicle, I am betting it will need to go at least 1 leaner, be real hesitant to go more than 2 leaner as that will throw that carb out of balance.
What you are really looking for is to be able to get those vacuum secondaries to open, that will be the challenge for you. Most people don't ever pay attention to this and in a mismatch like this they never have the vacuum secondaried EVER OPEN, and they never even know it.
Trust me you will know when they open, and its not like a holley opening.

After getting the secondaries to open the next most important thing is to eliminate that off idle stumble, this will be because the initial pump shot is inteneded for a LARGE displacment engine and you will want to back it down until the stumble ideally goes away or is diminished.

Then after all that try to get this to idle smoothly, do that by bumping up the timing and playing with the idle mixture screws a tach and a vacuum gauge.

Given your two choices I would go with the replacement carb but good luck it is still going to take soem to make this tick good.

Bill White
White Automotive