79 cj 5 carb problems? i think

[kdoubleu105]

i recently picked up a 79 cj5 with a straight 6, ran sweet for about a week the all of a sudden starting goin downhill fast, running realy rough, especialy under load, my plugs were turning black quick but not wet with oil, smells like fuel, i put new plugs in and it ran great again for about 10 miles or so then started acting up again, i then bought a carb rebuild kit and that didnt help me much, ive tried to adjust some things but im not sure what im doing, i think its something with the choke,, oh and theres a good amount of black exhaust coming out, i also did a compressiion test on each cylander and they were between 100 and 115, i beleive that this is low?? any suggestions would help i dont have alot of money to pay a mechanic so now it sits in the driveway,,, thanks

[Shadly1]

i recently picked up a 79 cj5 with a straight 6, ran sweet for about a week the all of a sudden starting goin downhill fast, running realy rough, especialy under load, my plugs were turning black quick but not wet with oil, smells like fuel, i put new plugs in and it ran great again for about 10 miles or so then started acting up again, i then bought a carb rebuild kit and that didnt help me much, ive tried to adjust some things but im not sure what im doing, i think its something with the choke,, oh and theres a good amount of black exhaust coming out, i also did a compressiion test on each cylander and they were between 100 and 115, i beleive that this is low?? any suggestions would help i dont have alot of money to pay a mechanic so now it sits in the driveway,,, thanks

If you installed a carb rebuid kit, how can you not know what you're doing??? You should be a pro by now! It definitely sounds like a carb issue. Sticky float maybe? If it's too far gone, you may want to pick up a rebuilt carb from your local Autozone.

[USMC 0369]

Check your intake manifold & carb for warp. My 74 was doing the same things (rebuilt carb also) and I started to spray some carb cleaner on different areas (per Dad's advice) and found that my actual carb housing was leaking from being warped. I replace the whole carb and the CJ runs like a beast, when it actually runs. I've also had the intake manifold on the YJ warp away from the block twice due to excessive heat (won't go into that.)

[kdoubleu105]

right on thanks, ya i sprayed some carb cleaner on before it was running as rough as it is now and the idle changed, which i beleive means that theres a leak somewhere, , is there another way to check specificly for warp? put it on something flat, i guess???

[USMC 0369]

right on thanks, ya i sprayed some carb cleaner on before it was running as rough as it is now and the idle changed, which i beleive means that theres a leak somewhere, , is there another way to check specificly for warp? put it on something flat, i guess???

Yep, you have a leak somewhere if it's changing idle when sprayed. I used the little hose on the carb cleaner bottle and it pointed out exactly where the leak was for me. It could be nothing more than a leaking manifold or carb gasket. I found my warp in the carb housing by pinpointing the location of the leak; then by doing a visual inspection of the area I saw it was warped. Otherwise, I'd use a carpenters square or get a straight edge.

[rick]

Usually on the Carter carbs the upper carb housing is a cheap, potmetal cast POS that warps. The lower piece is a little better quality metal. The mating surface between the upper and lower carb body is possibly leaking. You can use a high quality motorcycle sealant rated for fuel service (I like Yamabond 4). That stuff will seal it, or at least it worked on mine. However, I suspect that since you are running rich rather than lean, I'd look for fuel delivery problems, i.e. stuck float or choke. You are probably spraying the cleaner at the throttle shaft, which if the carb is more than a few years old, is certainly leaking. This is not the end of the world unless it's really sloppy, it can be tuned out by adjusting the mixture screws once you figure out the rich condition cause.