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Post by leecarr on Apr 2, 2017 17:42:28 GMT -5
First off I have read about every post and viewed every video here multiple times. I have what I believe is a 636 but I'm sure it is a W-O. Engine is a 54 Henry J supersonic running 12v, new parts include electronic dist., coil, plugs , wires, head gasket, intake gasket, fuel pumps. Carb rebuilt with kit from Peter Debella, metering rod gauge from Jon Fitzpatrick. Almost 120 psi compression in all cylinders. Carb has been apart 4 times and all adjustments are right on spec. Timing was adjusted with vacuum gauge to around 18 at best idle, waiting for tach/dwell meter to check rpms. Right now running an electric fuel pump with about 7 psi, tried a new and a used mechanical fuel pump with no difference with problem. With full choke engine starts and runs fine but as soon as choke is backed off at all engine stumbles and dies and idle mixture screw seems to do nothing at all. I have checked everywhere with starting fluid and there are no vacuum leaks. Timing seems to be right on, moving dist. makes it run worse. Did the same thing with another rebuilt carb ( I can see screwing up one but not both). I have tried what I believe is everything more than once and can't get anywhere. Any ideas. I have been playing with this stuff for over 40 years and have never seen a problem like this. Thanks in advance for any    help.
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Post by Scoutpilot on Apr 2, 2017 19:30:41 GMT -5
From which port did you draw your vacuum reading? Vacuum drawn from the throttle flange won’t give you an accurate reading. You need post-throttle vacuum normally found in the intake manifold only. Another point. Your rubber-to-steel connections for the fuel bother me. Is the rubber slipped over straight cut steel? If so, not good. The single clamp often causes the rubber to “bunch” up and create channels which allow air infiltration which enters the fuel stream and displaces the fuel. I suggest either all steel and brass, my favorite for security purposes. (One exception is the connector from the frame fuel line to the fuel pump. It must be rubber for the sake of motor vibration.) Or, all rubber and barbed brass with double clamps at each connector.
Check ALL of your vacuum lines/ports on both sides of the motor and don’t forget the wiper supply line, if vacuum-powered. As well, 7psi fuel pressure is a bit excessive. After shutdown, look down the barrel of the carb and watch for fuel entering the barrel. This would be indicative of over-pressurized fuel in the bowl. It could be the pump, but it could also be a malfunctioning/inoperative heat riser valve. Things to think about.
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Post by rickg on Apr 2, 2017 19:35:49 GMT -5
The rubber hose from the throttle body terminates where?
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oilleaker1
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Post by oilleaker1 on Apr 3, 2017 6:20:53 GMT -5
Having to run with choke is a sign of a vacuum leak . Stuck open PCV valve, too tight of valve clearances, leaking intake gasket, cracked intake manifold, leaking base carb insulator block surfaces, and if you are running a vacuum advance distributor with that black rubber hose, a leaking vacuum advance pot.
The throttle shaft in the base with the butterfly, is it good or very loose and worn? Oilly
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rudycon
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Post by rudycon on Apr 3, 2017 8:42:21 GMT -5
Hmmm. Idle screw doesn't do anything? Sounds like somethin's plugged up. Did you try the old "I don't want to take this carb apart just yet" trick of briefly sticking your hand over the intake horn with the engine running to try to suck the bit of dirt through (or deeper into) the carb? Works wonders.
You already did that? I think you just have to take it all apart, drop the main jet in the gravel driveway, spend 2 hours relocating it, then stick thin wires through the passages to get the corrosion from the ethanol fuel out of someplace.
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Post by leecarr on Apr 3, 2017 16:27:31 GMT -5
I'll try and answer all the questions at the same time. Hose on throttle body goes to vacuum gauge, manifolds were separated, cleaned and cerakoted, heat riser works perfectly, all new gaskets. Brand new breaker less dist. with electronic advance, wiper port plugged. I ordered a fuel pressure regulator and my tach/dwell meter came today but has a broken needle so I have to send it back. I have checked every inch of engine for vacuum leaks several times, had one at intake, replaced manifold and fixed that before any of this. All linkage and shafts were cleaned and cerakoted, shafts seem to fit good. I will move vacuum gauge to wiper port and plug throttle body port and correct fuel lines, using all brass plugs and fittings. Carb. was soaked in carb. cleaner and every hole was cleaned with a wire of proper size and compressed air, carb has been apart, recleaned and adjusted 4 times. I have no idea when the last time this thing ran, it was bought as a donor vehicle and I'm trying to get it running right so I know what I have. It is running 12v and is running on a fuel tank with all new line. I can't think of anything else, this thing is driving me nuts. I raised the metering run a tiny bit but that had no effect.
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Post by Scoutpilot on Apr 3, 2017 16:33:57 GMT -5
Check the vacuum at the manifold and get a tach reading and a dwell reading. Let us know the numbers you come up with. Is there a new diffuser gasket under the carb? If so, check to be sure the copper rings that slip over the studs are flat as the gasket itself. improperly tightened (<33-35 ft/lb) will give you a vacuum leak.
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oilleaker1
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Post by oilleaker1 on Apr 3, 2017 18:15:28 GMT -5
You also didn't verify if the valves are correctly adjusted and the PCV valve is functioning correctly. Thse both will give you problems like you have. John
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Post by leecarr on Apr 3, 2017 18:25:47 GMT -5
PCV valve was taken apart and cleaned and is fine, new diffuser gasket with copper inserts flattened. No detectable vacuum leaks. I have to get a new tach/dwell meter. I have not checked valves but compression is good and consistent in all cylinders. Valves looked good when I had head off and I installed new head gasket.
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Post by Scoutpilot on Apr 3, 2017 19:09:41 GMT -5
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Post by leecarr on Apr 3, 2017 19:38:00 GMT -5
Sure did, it was in great shape cleaned it out good and reassembled it. Ordered new meter, should have it by friday. I didn't even know it came apart until I looked in the manual, I have an original Jeep service manual, well worth the money pictures are so much better.
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oilleaker1
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Post by oilleaker1 on Apr 4, 2017 5:23:15 GMT -5
Holy Cow, sounds like you need to begin eliminating things, one item at a time. If you know a fellow Jeeper, have him try your carb on his known good running Jeep. Obviously something is still wrong and it got missed. Fixing everything at once, leaves you in a mess to trouble shoot the problem. John
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Post by leecarr on Apr 4, 2017 9:58:01 GMT -5
This wasn't all done at once, this is just a list of things that have been done one at a time over a period of months to eliminate problems. A friend of mine just rebuilt his motor and hasn't run yet. No one else close, all the "old timers" that knew this stuff are gone. I'm going to make a few small changes and get some new numbers when my tach/dwell meter comes in. This should be a simple fix, a lot of motor heads in and out of here all the time, my father had a bunch of these in the 50's but this has everyone stumped. I'm trying to avoid adjusting the valves but compression is steady and consistent in all cylinders, the vacuum gauge was steady with no jumping around too.
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oilleaker1
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Post by oilleaker1 on Apr 4, 2017 14:15:31 GMT -5
Try one more test. Get her running, manually turn off the choke, and slowly spray carb cleaner into the intake cross over tube at a idle and see if she will pick up and run. If it does, you have poor/no slow speed circuit fuel. The slow speed jet may be too small, or has become plugged on you. I'd set your idle mixture needle at about 1 1/8 turn out from bottoming. Scout, jump in here, how many turns out is normal on the idle stop screw that opens the butterfly? If it will idle with this test, it's back to the carb. Maybe find your old original slow circuit jet and compare or install the old one. John
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Post by leecarr on Apr 4, 2017 14:51:38 GMT -5
 I don't have the cross over tube on but I don't think it will make much difference if I spray it directly in the carb as long as I go easy. The line from the tank to the pump was replaced by 1/ 4 copper but I'm not using it, the rubber line I'm using is 1/ 4 not 5/16 could that be a problem? I have been wondering about the accuracy of this metering rod gauge since I got it, appears to have just been ground by hand. I have a bunch of old needles and seats but I'm not sure which ones went together. Does anyone sell just those parts so I can be sure of getting a quality one? I did adjust the metering rod up a bit but it didn't change anything, it's easy to do so I may try it again. Thanks again, you guys know all the tricks. |
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help. 
