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post #1 of (permalink) Old 03-29-2000, 06:22 AM
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stalling / vapor lock

My '81 CJ 7 w/a weber carb. starts, idles, and runs fine even when cold. After any short, 20 minute, trip, it starts easily again. Then w/in minutes it wants to stall, or does. If it stalls, it is very hard to restart. If it starts, it will idle a little. Any attempt to give it gas and it stalls. After giving it another break, it will start and run fine. I'm guessing this is vapor lock. However, I really don't know. I'm wondering where to start.

Last year I installed a new Weber carb on it. Everything was great. It started right up and idled when cold. It also felt like a substantial increase in HP. About a month ago I had the fuel pump replaced. Shortly after that it nearly went up in flames because the hose coming out of the fuel filter was very loose.

I just recently moved so my jeep is one place, my manuals are another, and the Weber carb instructions are yet a third. I' appreciate any help while I'm trying to find the time and manuals.

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post #2 of (permalink) Old 03-29-2000, 07:42 AM
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Re: stalling / vapor lock

[img]/wwwthreads_images/icons/tongue.gif[/img] By any chance did one of your moonguy[img]/wwwthreads_images/icons/wink.gif[/img][img]/wwwthreads_images/icons/smile.gif[/img][img]/wwwthreads_images/icons/wink.gif[/img]crew take off the three-port fuel filter thinking: "Boy....this'll make it go TWICE as fast!" If so, that's the problem. You need a three port filter.....the third port is the "return to base" for the extra little gas guys, and the third port needs to be ON TOP to get rid of the air bubbles.[img]/wwwthreads_images/icons/crazy.gif[/img]

CJDave
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post #3 of (permalink) Old 03-29-2000, 02:41 PM
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Re: stalling / vapor lock

If that isn't it then make sure that your fuel lines are not near a heat source. If your exhaust is bad and blowing on your gas tank it can cause vapor lock too.
Aaron

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post #4 of (permalink) Old 03-31-2000, 05:55 AM
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Re: stalling / vapor lock

I'll check the orientation of my 3 port fuel filter and the routing o my fuel lines.

Thanks,
Dave

post #5 of (permalink) Old 03-31-2000, 06:58 AM
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Re: stalling / vapor lock

I had a similiar event with my 1980. My problem turned out to be debris in the fuel line, at the tank. Easy repair, though maybe temporary, remove the gas filler cap, loosen the inlet hose at the fuel pump, pump some air back in the line towards the tank. Don't over do with the air pressure.

post #6 of (permalink) Old 03-31-2000, 09:47 AM
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Re: stalling / vapor lock

Another common problem on older vehicles is the fuel line between the fuel pump and gas tank. Two places to check..the rubber line on the intake side of the fuel pump, and the rubber fule line between the gas tank and the main metal line that runs down the frame. What happens is that the lines get old and start to crack. They don't leak gas, but they will let air get sucked in, hence it feels like a vapor lock. Since your fuel pump was recently changed...and it was after that the problems started...I bet its the rubber line there.

FYI....about the only vehicle I have ever seen get a vapor lock was a VW Beetle.

John......southern CA
84CJ7, 3"lift, 32"BFG, 4.10's, ARB Locker, Solid Axle's, Durabak
post #7 of (permalink) Old 03-31-2000, 04:04 PM
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Re: stalling / vapor lock

Wow, I'm gonna feel strange here [img]/wwwthreads_images/icons/crazy.gif[/img], but I gotta disagree with CJDave's Moonguys. [img]/wwwthreads_images/icons/wink.gif[/img]

You don't *need* the 3-position fuel filter. The stock mechanical fuel pump has a check valve in it, and the system will work fine with a regular ol' fuel filter in the line, and a disconnected return line. I've been running my weber'd YJ for about a year this way, and have done some hot summer wheelin' with no vapor lock problems. I did it to help the infamous "drainback into the tank" of the weber. I used a simple clear plastic fuel filter so I can see when it gets crappy, and it works great. If you do have vapor lock issues, you can get some heat tape/tubing/wrap stuff at most autoplaces or JC Whitney, and put it over the line going from the pump to the carb. I have not had to do this yet.

Your problem sounds like it could be a stuck linkage, a stuck float in the carb, a misadjusted or disconnected choke... etc. Does it blow black smoke when it does start?

I also have the weber instructions for the 32/36 scanned in, and can email you those if you're interested.

Just my opinion
Good luck,
Pete

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post #8 of (permalink) Old 04-03-2000, 12:04 PM
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Re: stalling / vapor lock

Thanks plenty. You guys have given me some hope. While unpacking my Garage stuff this weekend I wondered by the Jeep one too may times. I was compelled by the force to lift the hood. Upon looking at the rubber hose leading to the fuel pump, I noticed it cracking. Thought to myself, I better replace this once unpacked. Well needless to say, I didn't get the garage and basement done before the weekend ended. So, today I read the posts. And what do I find, someone who had problems with this cracking.

Also, I plan to raid my in-laws this week for more of my stuff, including the carb. instructions. Thanks for offering the scanned copy.

Thanks,
Dave

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