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78 CJ5 304V8 problems

247 Views 0 Replies 1 Participant Last post by  wnimocks
Hello, I've grown up working on stuff, but am getting over my head on this project. I have a 78 CJ5 with at 304. Bought it used a few years ago. It ran fine until recently, and I've noticed the following issues.

After I let it sit for 4-5 days, it won't turn over when I crank. Seems like it's starved for fuel. (I replaced fuel pump, fuel filter and fuel tank about 2 years ago). I get it started by pouring gasoline directly into the carburetor and when it starts it blows black gunk out of the exhaust. It will back fire 2-3 times through the carb, and then warm up normally. After about 3-4 minutes, idle is smooth and it runs normally for a 10-15 minutes.

Then after I run an errand or two, it leaves me stranded. It dies usually after about 10-15 minutes of running. The motor is really hot! So I replaced the water/antifreeze and hoses recently, but maybe there's something else going on, like a clogged radiator or water pump issue. I let it cool off and get it started so I can get home.

That's when I started thinking that may be I have a water pump and fuel pump issue. Is it the same mechanism that drives both pumps??? I know I need to tune up the carburetor, and check the timing. What else could cause these issues? sticky fuel? vacuum issue? dirty heads? clogged radiator? all of the above?