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Discussion Starter · #1 ·
OK. I own a 76 cj-7 with a 304...INITIAL problems-engine dies without warning, may sputter then get better. Changed entire (module, coil, distributor -rmfg-, cables, plugs) ignition minus timing gear. That cured the lack of spark. Next problem. starts doing the same with exept black smoke and backfiring. Cure? new fuel delivery system (rmfg carb, fuel filter). Now that it doesnt die when it feels like it, it bogs down when I shift from 2nd - 3rd and 3rd till i get up to speed. My jeep does not have a tach and have tried to adjust mixture on the motorcraft 2150 carb (76 era)and changed the throttle cable to the 2nd hole. it seems to level out when the jeep gets to a good running temp but from cold to warm it sputters until the rpm's pick up. anybody have a similar problem?


Scott,
76304150202030
 
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Discussion Starter · #2 ·
Its gotta be a carb problem... I had a similar problem and it was with the
air fuel ratio.... I had a AIR jet that was too big and it would idle great until
it got warm and opened up all the way... Then it would buck act like it was
running lean and would backfire. You might try taking it to a carb shop and
letting them put it on a machine to find out what it might be. You could throw a
rebuild kit into it for about $20... Thats all i got. Definatly the carb tho.
Dustin

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/wwwthreads_images/icons/tongue.gif What about the exhaust gas recirculator valve? Do you have such a thing on your '76, and is it functional? What about fuel flow? You are obviously getting fuel, but how MUCH fuel? Enough to idle on but not enough to run perhaps? Is the intake manifold leaking where it hooks to the heads? Did you gently spray WD-40 into all the little spots and check for leaks? What about the POWER VALVE in that carb? Are you sure it is OK? Are the distributor weights free and functional? Is there an exhaust restriction, like a plugged up catalytic converter? Is the exhaust heat riser free and operable in the Right Hand exhaust mainfold? Are you cross-firing in the distributor cap from moisture or from a coil that is too hot for the stock cap and rotor? Are you CERTAIN of the firing order and is the rotor perfect on the cap terminal when it fires? My personal bet is on the fuel supply. I think that there is a restricted fuel flow, and the moonguys think so too./wwwthreads_images/icons/wink.gif/wwwthreads_images/icons/laugh.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.
 
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Discussion Starter · #4 ·
wow. lots of questions i havent the slightest about. it has a brand new remanufactured carb on it. the right header does have a rust hole in it BUT it didnt effect it when the old carb was on it. the air heater (from manifold to air cleaner assembly) was replaced to heat it quicker. from all indications, it was running too rich (this was when it was really bad) so my dad tried to lean the mix...helped, but it still lags when shifting from gear 2 and up...and when its cold i is a violent missing lag...when its warm its just sluggish until it i get some speed on it...hope this makes sense.


Scott,
76304150202030
 
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Discussion Starter · #5 ·
the OTHER answers. the coil/distributor are both stock replacments, when i changed carbs i also changed plugs b/c tho old ones were way fouled. after a coule miles of driving the new plugs were also fouled. so..thats when we leaned the mix...dont know about the power valve (no clue what it even is, but if its on the carb its new)...hope that makes more sense.g


Scott,
76304150202030
 
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Discussion Starter · #6 ·
i have opposite symptoms. it runs good with the exception of when i shift gears and it hasnt warmed yet...it basically bogs down...i plan to take it to a carb shop when i have it reinsured.


Scott,
76304150202030
 

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I'd agree with the others in that it's the carb. Just because it's new/reman doesn't mean it's good or set right. I've known of new/reman carbs not working and being returned 2-3 times. Either get it checked at a carb shop or learn about it yourself. The best way to do this is to get the FSM or at least a Chilton's/Haynes and read about it. This is what I have done, repeatedly, and it's helped a lot. Even if I can't always fix it myself, at least I know what to look for and what I'm talking about if I take it somewhere. Sorry this isn't a great answer but I would check the carb. Regards,
fratt77cj7

fratt
 

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The 2150 carb is it a new manufacture or is it a new rebuild? The 2150 is natorious for warping along the base plate and this is very easy to detect by putting a straight edge along the bottom of the base before installing to check flatness. Also the 2150 is the easiest carb there is to check for feed and float levels as you can remove the top and run it on the motor to check both of the latter. (of course this means not driving it with the top off) As this carb was made for a lot of motors for AMC and Fords. The power valve located just under the bottom front corner of the bowl can have a correct valve installed and still not be correct for the exact motor you are using,(did this make sense to you). Also do you have the Delco ignition system or the Prestolite system? Can't remember which it is but one uses a external risistor on the ignition and the other uses internal, this may or may not effect the firing, depending if the components were mixed. Another thig to check is the exhaust flow, has it got enough room to breath?

GP'n

 
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Discussion Starter · #9 ·
thanks all. i have a plan of action now-
take to carb shophave them look/adjust
take to muffler shop and have jc whitney free flow dual exhaust put on

if that dont fix it, ill just have to disassemble the thing replace every part with a new one.


thanks again
scott


Scott,
76304150202030
 
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Discussion Starter · #10 ·
Dave, I am surprised you forgot to mention carb icing. If the heat riser tube is missing and the air temp is right. You get the picture.
CJ-Rick

 

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What about the vacumm system. If I'm remembering correctly isn't there a contact on the transmission that when shifting into third (on the threee speed) sends an electronic signal to the vacumm system to close a port?
What about PVC valve? EGR needs to be thoroughly checked.

 

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/wwwthreads_images/icons/crazy.gif Carb icing IS a problem, but it is rare on V8s. Huge inline engines, especially those with updraft carbs will ice up like crazy. Our International RD 450's had a carb heat lever to get warm air to the carb....they would ice up easy at a low power setting./wwwthreads_images/icons/crazy.gif Heh heh....I was looking at your profile Rick; Wow! A Jeep with a Cummins Diesel and an Allison transmission! That's really something! Six-wheel drive, too! Yow!/wwwthreads_images/icons/crazy.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.
 

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a couple of winters ago, i was having problems with the motorcraft carb on my 304 icing up. the venturies were coated with ice. this was in just barely above freezing temperatures. i put a heat riser tube between the exhaust manifold and air cleaner and hooked the vacuum line on the air cleaner back up. (they we're there when i bought it.) that solved the problem.

79/CJ-7/AMC360/TH400/Q-TRAC/d30/d44/33's/RS9000s/Herculiner
 

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/wwwthreads_images/icons/shocked.gif Why, I'm shocked.....I had NO IDEA that a V8 would do that. We have a hot air tube on our 304 as well, but I thought it was for the emmissions to get better faster on cold mornings. Well that shows you one thing.....there is good venturi action in that motocraft./wwwthreads_images/icons/crazy.gif

CJDave
I never believe any statistics unless my moonguys /wwwthreads_images/icons/crazy.gif/wwwthreads_images/icons/wink.gif made 'em up themselves.
 
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