Author Topic: 74 CJ5 with AMC 304 Running rough  (Read 1441 times)

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TrailsLessTaken

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74 CJ5 with AMC 304 Running rough
« on: November 26, 2008, 07:45:56 AM »
Im trying to help my buddy get ready for our trip to Redbird this weekend.   He has a 74 CJ5 with the 304, the motor is stock and had an aftermarket carb on it when he bought it that was way to big.  He just bough the Holley Truck Avenger 470CFM carb, got it put in took it to the mechanic and had him fine tune everything.  Drove it home ran great, went out to start it the next day started up fine then after a few minutes just went to crap.  I checked the fuel pump and its working fine everything electrical is has been rewired or is brand new.  Anybody have any ideas
« Last Edit: November 26, 2008, 07:46:10 AM by TrailsLessTaken »

Offline VA_YJ

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Re: 74 CJ5 with AMC 304 Running rough
« Reply #1 on: November 26, 2008, 03:00:51 PM »
OK, yes I'm old guy, so I have messed with carbs a bit.  I am wondering about the choke.  If he has an automatic choke, you need to make sure the choke is opening up after the engine warms up.  Otherwise the mixture is too rich.  Automatic chokes normally have a bimetallic spring that causes the choke plate to open once the spring gets warm.  Electric chokes use a resistance heating element to warm the spring.  Other designs have a heat tube that draws off the exhaust manifold.  Common problems: choke adjusted incorrectly (loosen and rotate to adjust), no power to heating element, heat tube knocked loose.
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TrailsLessTaken

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Re: 74 CJ5 with AMC 304 Running rough
« Reply #2 on: November 26, 2008, 05:06:33 PM »
Its got an electric choke, but the problem now is I can't even get it running long enough to let the engine warm up.  He drove it home it home the other night when it was about 30 out and said it ran fine, but now that we plan on leaving, his jeep just decided it doesnt want to go at the present moment

Offline aw12345

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Re: 74 CJ5 with AMC 304 Running rough
« Reply #3 on: November 26, 2008, 05:18:29 PM »
Describe the problem more in depth does it lope and smoke black? or simply does not want to rev up and dies when you hid the gas?
If its the first description what happens if you manually open the choke blade?
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TrailsLessTaken

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Re: 74 CJ5 with AMC 304 Running rough
« Reply #4 on: November 30, 2008, 02:44:33 PM »
Turns out it was the coil resistor on the firewall had gone bad and the guy he bought the jeep off of never fixed and the coil was getting a full 12v instead of i think 7 so it would overheat the coil real quick, anyways problem solved