Just a nagging little problem with an old Jeep CJ that I've got laying
around. This Jeep has the original 258 straight 6 with a Carter YF (I
think, but won't swear that's correct) carb.
Everything starts and runs great, but if she has been sitting for about
3 days or more, it takes quite a lot of cranking before she fires up. My
best guess is that the float bowl is draining during this time and it
just takes a bit to pump more fuel up into the carb. If she's only been
sitting for a day or so, she fires right up seemingly on the first
I have not noticed any leaks or anything that would indicate the fuel is
dripping out, so the question is... where can it be going? Or am I not
even thinking of what the real problem may be?
Some carburetor castings are a little porous and so the fuel may "bleed"
out all over the carb rather than in one concentrated drip. Also, 3 days
is enough time for a lot of fuel evaporation to take place, so it may
just be the nature of the beast.
The most usual cause for that is the gas filter being installed upside
down. The filter has two outlets, the center one goes to the carb and
the 'top' one goes to the return line. If this return line isn't at the
top, gas will siphon back to the gas tank when it sits causing your
The second cause is a pinhole leak on the suction side of the pump.
Usually these happen at the flex lines or where the clamps hold the
steel line to the frame. It will just show as a stain at first because
it is a suction line, but it is enough to let air in when it sits.
Third and the most unusual is a failure in the pump's back flow valve.
You can check this by having it running, then shut it down and unhook
the inlet to the pump to see if gas drains out.
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pictures.html?id !15147590
(More Off Road album links at bottom of the view page)
Thanks Mike, You nailed it. I had two of the three problems you listed.
I'd never heard that the fuel filter needs to be installed with the
return line above the carb feed. Makes perfect sense now that I think
about it though. I had to rotate mine 180 degrees.
The rubber line that is the feed to the fuel pump had many cracks in it.
As a matter o' fact, it appeared to be an original because the clamp on
the fuel line side was one of those crimped on types. I replaced that
chunk of fuel line.
A 24 hour test had her start right up, now she's sitting for a few days
more to see what happens.
You are welcome.
I too had the filter issue, but was reading my owners manual and there
it was, the directions on the positioning.
I also believe this is one reason some folks cry that their 258 runs out
of gas on a steep climb. I go up sand pit walls and have never had a
gas supply stall.
I always thought that was from tipping the float bowl at a high angle.
Now I'll have to go climb a hill and see if that works better as well.
This old Jeep suffered from that problem for many, many years. On mine,
it seemed that I'd have to be bouncing as well as climbing to get that
It wouldn't actually stall, more of a severe stutter in my case anyway.
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.