Engine Need advice. 84 CJ7 I-6 140k ran good for a week after purchase. Fuel issue?

[Ridge Runner]

Need advice. 84 CJ7 I-6 140k ran good for a week after purchase. Seller said sometimes have to point downhill to get to start. So I'm thinking float bowl adjustment. Nope. He Nuttered it, best I can tell did right. Started shutting off on up hills then wouldn't start until sitting 10 min. Tried removing gas cap nope. Not overheating, blew out supply line it was fully open. Return line had to use a compressor but it worked but still has significant back pressure. Changed manual original fuel pump, pumps alot higher psi well above 15psi. Has clean 1 in 3 out filter with small line on top. Carb floods now runs rough & getting rougher after finally starts pours black smoke out tail pipe. Replaced carb with basic off Amazon. Same issue. Thinking vacuum lines or tank return not flowing good & guessing plugs are fouled now after all that gas dumping into intake. Previous owner put new plugs, wires & dizzy cap & button but that's it. Timing could be off as it was running little rich when got it definitely getting gas too much now. But ran good for a week, I'm stumped & went by 7 shops today. They all said don't work on carbs & pointed to a few old timers that do. Only 1 said he'd look at it in a few weeks. Would have to have it towed there. Any suggestions?

 

[KRUPP]

Maybe the tank return line is the culprit.
Pull it at filter, install a temporary shorty line and daylight it into a fuel can and fire it up it. If it runs better, you might have to replace that line and/or check it at the tank.

 

[hole]

Krupp's idea is where I would start. Does it look like any of the fuel lines (supply or return) have been changed recently? Wondering if someone used line not compatible with todays fuels.

 

[TSB8C]

Wondering if someone used line not compatible with todays fuels.

Agree with Krupp as place to start. And what Hole said - I've seen cases where vacuum line was used for the return by someone not knowing what they were doing.

 

[Ridge Runner]

Thanks for the help. Cut access panel to the sending unit from tub above and found the return line was pinched shut. Whoever put a poly tank in prior to me didn't run it through the bracket to keep it off the bottom of the tub. I ran it properly thru bracket and I'm able to blow through with just lung pressure now, prior took an air compressor. Still seems to be running a little rich. but I feel like that was the biggest problem. Pulled plugs they were completely black choked the motor down with seafoam and let it sit for a couple hours. Hopefully that got a lot of the carbon out replaced the plugs with new ones. Running much better, just need to get the carburetor or timing set to lean it up any suggestions? Pic is what I saw when opened it up.

 

[hole]

Cant help much with carb and timing, been a long time since mine had a carb. Glad its running better and it sounds like you've knocked out the biggest issue!

 

[Belizean]

I could have used that access panel a couple of weeks ago when we had to drop the tank in mine out on the trail outside Moab. Been thinking about it for years, but when you have had your Jeep since new for 40 years and practically rust free, it’s a very difficult thing for me to just start chopping.

 

[KRUPP]

That’s good to hear we were barking up the right tree.
Can’t help with the carburetor either; I have TBI.
I’m positive you’ll get help here though. Either someone will chime in, or you’ll find something in the “search” feature.

 

[TSB8C]

I did the access panel in my floor without hesitation. Did it in another CJ years ago and decided right off the bat to do this one when I installed the EFI engine. This allowed me to do the in-tank pump/float assembly. Of course I haven't owned my from birth, so not that level of attachment. And since I also cut/welded/changed other stuff as well, didn't matter to me.

 

[Patrick]

Vehicle manufacturers have caught on with this trick. Took me longer to diagnose than to replace the fuel pump on my gf’s Beetle.

Our VIN’s no longer reflect our rigs. May as well make our lives easier and modify as needed. You won’t regret a thing. Just make sure to measure a thousand times before butchering.

Consult with an expert auto body guru and make this mod look like factory.