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Unread 08-22-2013, 05:41 PM   #16
81azcj7
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That might be your problem I've always put them on both sides clean without any rtv. This goes for applying to the head or carb. Any one else have input?

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Unread 08-22-2013, 05:46 PM   #17
Matt1981CJ7
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What distributer?

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Unread 08-22-2013, 05:52 PM   #18
WSS
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Does your engine use a exhaust manifold crossover under the carb to warm it up faster in cold weather? I have that on my sbc and found (when I installed a rebuilt q jet) that the very high (359 degrees) under carb temps were causing the fuel to "boil" over and get pushed into the manifold when warmed up, cold it ran like a champ. They sell a phenolic spacer/isolator for my engine that should cure it but I chose to do a block off instead.

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Unread 08-22-2013, 07:13 PM   #19
Matt1981CJ7
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Quote:
Originally Posted by 81azcj7 View Post
That might be your problem I've always put them on both sides clean without any rtv. This goes for applying to the head or carb. Any one else have input?
I've always installed my carb gaskets dry, as well.

I'm pretty sure gasoline will destroy RTV.

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Unread 08-22-2013, 08:20 PM   #20
Koko4
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Carburetor gaskets are on dry - they are in this order.

[Carburetor]

[Paper Gasket] ->


[Spacer] (Firm rubber/cork-like material with SOME play)->


[Insulator] (Hard plastic)->


[Paper Gasket] ->


[Intake Manifold]


When I said I used RTV, I was referring to the intake manifold gasket itself, not the carb gaskets. There is a spacer and this insulator (as seen above) and the little bowl on my carb would hit the intake manifold without it being on there. So there should be ample space between the manifold and the carb.
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Unread 08-23-2013, 05:39 AM   #21
Matt1981CJ7
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Back to the basics...

1. Check everywhere for vacuum leaks. This is by far the #1 leading cause of most problems with CJ engines.
2. Check fuel pressure. I think the MC2100 likes 4-5 psi at idle, no more no less.
3. Confirm the bypass fuel filter is installed properly...filter should be at approximately the same height at the carb inlet, should sit level horizontally, and the return outlet should be in the 12 c-clock position.
4. Check float level.
5. Confirm the choke is operating properly.
6. Confirm the firing order is correct.
7. Confirm TDC of the compression stroke jives with the marks on your balancer.
8. Inspect plugs for signs of mixture or timing problems, and check for proper gaps.

I'll probably think of more when my first cup of coffee starts kicking in.

Good luck,

Matt
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Unread 10-29-2013, 06:48 PM   #22
Koko4
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Hey Matt, thanks for the suggestions. I have been tinkering with the Jeep off and on for the past couple weeks, and I THOUGHT I had it. I adjusted the idle mixture screws and now the Jeep will start, and then shut off if I don't continue giving it gas. I had to raise the idle a bit to keep it running, so it's definitely idling higher than it should be (I can hear it). I have timed it not with a timing light, but with a vacuum gauge hooked up to the manifold. Vacuum is reading in the exact center of the green region on the gauge. I was having problems earlier when I was trying to adjust the timing via the timing light - Jeep wanted to stumble and die anywhere close to 12 advance. I was doing it properly - capping off the vacuum advance and distributor port, and then using the timing light. I now have it so after I start it and get it past that first "want to die 30 seconds", it will idle fine and drive up and down the street with no hesitation. I even got on the road and floored it a few times, and it had GREAT pickup. After I drive for 20 minutes or so, it starts bucking / sputtering when I accelerate with any type of urgency. I thought I was having vapor lock problems, as my fuel lines are routed REALLY close to the exhaust manifold (see this thread: http://www.jeepforum.com/forum/f8/cj...ifold-1598913/). I wrapped both fuel lines in heat wrap sleeves, which seemed to help, but could be the placebo effect. I have checked all around the base of the carb for vacuum leaks using carb cleaner and starting fluid, have checked all capped vacuum ports and the area where the intake manifold mates to the head. No apparent leaks. Choke is definitely operating properly..it is a manual choke and I've tested it. Firing order is correct. Thinking about it, my fuel filter may be turned so the return line is not at the 12 o clock position. Would that really make this big of a difference? I will check the fuel pressure tomorrow, but what am I supposed to do if it is too high / low? I have replaced the rubber hoses that go from the tank to the fuel lines, as well as from the fuel lines to the fuel pump. The fuel pump is new. The fuel filter is new, and the carb is rebuilt / new. Thanks for the tips again. I keep getting discouraged and leaving it alone when I feel I have it "good enough", but I am going to try to stay vigilant with this thing and get it running like it should. I've put too much time and effort to have it otherwise!
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Unread 10-29-2013, 11:10 PM   #23
Koko4
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I also forgot to mention that my oil pressure starts out high (~60psi) when I first start the car, and will be around this number for the first 10-15 minutes, and then it will gradually go down and remain around 20psi at idle. Is that normal? I was assuming it was because I do have the idle set at a pretty high RPM.
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Unread 10-30-2013, 05:12 AM   #24
Matt1981CJ7
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I don't recommend timing with a vacuum gauge. It's likely to result in timing that's far too advanced. Do it right with a timing light.

The oil pressure is normal.

I've asked this before, but didn't get an answer. What ignition system are you running?

Matt
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Unread 10-30-2013, 08:37 PM   #25
Koko4
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Sorry - stock ignition system for a 304.. Advace Auto / Autozone coil, same with distributor, same with ignition control module. Nothing special! Should I time to about 12 advance with the light then?

I measured the fuel pressure as it was coming out of the fuel filter, and it was fluctuating from 2-4psi or so - the needle was really all over the place. Fuel filter was replaced recently..shouldn't have anything wrong with it. I measured the pressure before the fuel filter and it was hovering at 5psi - so I bypassed the fuel filter by using a long piece of hose straight to the carb, and plugged the return line. Thought the Jeep would run better but it was still doing the same crap. In the fuel filter, there are two holes on the carb side - one return and one feed. The feed is the one in the center, while the return is the one on the edge, correct? I will switch it back to that configuration tomorrow..
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Unread 10-31-2013, 01:47 AM   #26
Matt1981CJ7
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I'll never understand why the damn fuel filter is so hard for guys to get right

Take some good pics of your engine compartment. Maybe one of us can spot something obvious.

I'm still leaning towards a vacuum leak.

Matt
fuelreturn2.jpg  
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Unread 10-31-2013, 05:20 PM   #27
Koko4
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I hooked up the fuel filter again, and changed the timing just a TAD on the Jeep. The distributor rotor rotates clockwise, and I rotated the distributor a hair counter-clockwise. Am I correct in assuming this slightly advanced the timing? I drove it around for about 20 minutes and did not have the bucking / sputtering that I usually have. Usually this bucking will become more apparent once the oil pressure lowers at idle, to around 15-20psi, which is after about 15-20 minutes of moderate driving. This time, when the oil pressure lowered, it was still driving fine. I'm not sure if I've fixed the problem or not. I am going to take pictures tomorrow and post them on here - it is a bit hectic with all the Halloween festivities going on. I also messed with the mixture screws a bit..(richened the mixture some) and increased the idle a bit.
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Unread 11-03-2013, 12:31 PM   #28
Koko4
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Sorry it took a few days, but here are those pictures.

http://s1101.photobucket.com/user/Ko...%20Compartment














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