| len47merc | -- 03-31-2014 @ 6:07 PM |
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Removed the heads from a '47 59 A-B and found cylinders 5, 8, 3 & 2 were running rich and others perfect, this (running rich) both before and after earlier rebuilding the stock Ford/Holley 94 carb. Noted both jets were 51s and clean during carb rebuild. Also noted these cylinders are every other cylinder in the firing order (hmmm...). Do not have access to the intake at present to further review but assume these cylinders are all serviced by one of the barrels of the carb. Appreciate any thoughts on the root cause here and insight as to which carb barrel services these cylinders - driver side or passenger. Appears 51s are the correct jets, carb is clean/all ports flowing/fuel mist appears correct. Clogged/restricted intake (reaching deep there), distributor/spark issue (again reaching deep here) - just not sure at this point. Data points - original untouched motor with now 38K miles, new Autolite 216 plugs properly gap'd, all cylinders running 115-123 psi compression with no oil burn or blow-by. Steve This message was edited by len47merc on 3-31-14 @ 6:16 PM
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| ken ct. | -- 03-31-2014 @ 10:44 PM |
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I think your on the right track,could be an unmatched pair of nozzle bars or the long idle air jets have a bigger or smaller hole in 1 of them.Not sure of what side controls those cyl but its worth checking. Do jets measure the same. I don't mean the # on them either. Check sizes w. a pin gauge. OMO. ken ct.
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| len47merc | -- 04-01-2014 @ 4:04 AM |
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Eyeballing, these '51' labelled jets look identical but my eyes haven't been calibrated in a while. Will pin them later today. Had not yet considered the idle jets - will check those as well. Have to think this carb is worn somewhere/somehow. Steve This message was edited by len47merc on 4-1-14 @ 4:05 AM
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| ken ct. | -- 04-01-2014 @ 4:52 AM |
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Do you have access to another carb from a friend to try on it. I can send you one of my rebuilts if you want to go that way. Payment can be made after you try it and its normal again otherwise just send it back to me with mailing cost to me. ken ct. Sounds like somethings is OS in there.Best I can do for you call if you want. 1-203-260-5945 cell. be back in an hour.
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| carcrazy | -- 04-01-2014 @ 9:41 AM |
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All of your rich cylinders (2,3,5&8) are fed by the passenger (right) side barrel of the carburetor. I would check everything that controls fuel flow through this barrel. The items to check are: main metering jets, idle jets, power valve jets, idle air bleeds, air bleed plugs (aspirating nozzles), idle mixture adjusting screws and seats, and all gaskets and sealing washers in the fuel and metering circuits. Be sure all of the passages in the carburetor are clean. I would especially look for a blockage in the air bleed passages which would cause the fuel/air ratio to be richer.
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| TomO | -- 04-02-2014 @ 6:24 AM |
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Steve, The carbon deposits that you see in the cylinders could be from before you rebuilt the carburetor. When you get the car back together and running, check the idle mixture by turning in each mixture screw until it bottoms and then back out 1 turn. Start the engine and adjust the mixture screws in together 1/8 turn at a time. When the engine begins to stumble, back off 1/4 to 1/2 turn until the engine idles smooth. Both screws should be adjusted the same amount.If you have a vacuum gauge, connect it to the wiper port of the intake and fine tune the mixture for the highest steady vacuum. If you cannot get a good adjustment doing this, you need to check out the carburetor and ignition system. Next, check out the high speed mixture by putting in new plugs and taking the car out for a long ride of 1 hour or more and then bring it home and shut it off without letting it idle. When it cools down, check the plug color for mixture. If the plugs are normal, then your driving mixture is OK. Tom
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| len47merc | -- 04-03-2014 @ 4:07 PM |
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Good Tom - thanks, will do. Carcrazy's confirmation of the passenger barrel is appreciated as well. The carb was so clean and all ports verified for openness that I am stunned to see one side producing such a rich result and have to agree you at this point on the 'prior to carb rebuild' case. The idle mixture was set after carb rebuild using the '1 turn out, 1/8 in' process but the vac gauge is coming out of storage after this episode. Will update after the 1-hour ride/quick shutdown/plug review in a few weeks after motor reinstall. Steve
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| len47merc | -- 04-08-2014 @ 5:14 AM |
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Gents - after review of the disassembled carb all that can be found that varies significantly barrel-to-barrel is a much more rounded and worn right side idle mixture screw. As noted above, previously after the carb rebuild the motor idled smoothly and responded normally to the 'full in, one turn out, 1/8 in' process so am questioning whether this could be the root cause. Still plan on employing Tom's advice on the hour-run/new plug review upon motor re-install in a few weeks, but want to ensure I've addressed all I can on this issue prior to that time. Steve This message was edited by len47merc on 4-8-14 @ 5:15 AM
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| ken ct. | -- 04-08-2014 @ 5:38 AM |
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Most decent kits contain new idle screws ?? Mine do anyhow. Hope yours contained correct and much better leather accelerator pumps and old school steel needle and inlet and 5.5 power valves not 7.5 # like most kits have.Sounds like you may have purchased a bummer China made kit. OMO. ken ct.
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| TomO | -- 04-08-2014 @ 8:03 AM |
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I believe that the idle mixture screw could cause one side to run richer than the other and still idle fairly smooth. I also wonder if the seat for the screw has been damaged. Now that you have the carburetor apart, I would put in a new kit. Ken Isador does supply a good kit, and is the only one that I know of that has the steel float needle. Tom
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| len47merc | -- 04-08-2014 @ 3:05 PM |
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Tom - you are probably already aware (meant to mention this in the earlier pm) that 'ken ct.' who had replied earlier in this stream is Ken Isodore. Ken had supplied his number in his first reply to this discussion which is how I happened upon him. Steve This message was edited by len47merc on 4-8-14 @ 6:18 PM
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