'88 YJ sputtering question

I have a '88 YJ with the 4.2 liter inline 6. The engine does have
quite a few miles on it but seems to do alright. The question I have
is why would it hesitate and sputter at low rpm's when I load the
engine? For example, when starting out from a stop? The Carter BBD I
rebuilt not long ago and now I just put a Motorcraft 2100 on and I
still have the same problem? Also, with both carburetors I can't seem
to get the idle rpms down from about 1000. What should I look at? I
have adjusted the idle screws and the mixture screws. In fact, the
idle screw isn't even touching now to get it down to 1000. Any help
would be appreciated.

Have you checked everywhere for air leaks or a missing/cracked/broken hose?

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"rjmax" > wrote in message
ups.com...
>I have a '88 YJ with the 4.2 liter inline 6. The engine does have
> quite a few miles on it but seems to do alright. The question I have
> is why would it hesitate and sputter at low rpm's when I load the
> engine? For example, when starting out from a stop? The Carter BBD I
> rebuilt not long ago and now I just put a Motorcraft 2100 on and I
> still have the same problem? Also, with both carburetors I can't seem
> to get the idle rpms down from about 1000. What should I look at? I
> have adjusted the idle screws and the mixture screws. In fact, the
> idle screw isn't even touching now to get it down to 1000. Any help
> would be appreciated.
>

Sounds like vaccuum leak



"rjmax" > wrote in message
ups.com...
>I have a '88 YJ with the 4.2 liter inline 6. The engine does have
> quite a few miles on it but seems to do alright. The question I have
> is why would it hesitate and sputter at low rpm's when I load the
> engine? For example, when starting out from a stop? The Carter BBD I
> rebuilt not long ago and now I just put a Motorcraft 2100 on and I
> still have the same problem? Also, with both carburetors I can't seem
> to get the idle rpms down from about 1000. What should I look at? I
> have adjusted the idle screws and the mixture screws. In fact, the
> idle screw isn't even touching now to get it down to 1000. Any help
> would be appreciated.
>

When I put the Motorcraft 2100 on I found a hose or two that might have
been a problem so I replaced them. I will check around for some more
vaccuum leaks. Thanks for the suggestions. Any other ideas?

That could easily be a dead charcoal canister. At idle pinch the line
from the back of the carb, off the PCV line, that goes down to the top
of the canister. There should be a solenoid thing or better a T fitting
in the PCV line. If the idle changes, the canister is dead or the purge
vacuum isn't plumbed right.

The canister should only be active when hot via the CTO valve and when
running by using a ported vacuum signal.

On the BBD, the ported vacuum was up top on the valve cover side. Don't
know on the 2100.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

rjmax wrote:
>
> When I put the Motorcraft 2100 on I found a hose or two that might have
> been a problem so I replaced them. I will check around for some more
> vaccuum leaks. Thanks for the suggestions. Any other ideas?