CJ - backfiring problem help (a little long)
06-13-2006, 11:23 PM
#21
Guest
Posts: n/a
Re: CJ - backfiring problem help (a little long)
"Hootowl" <ELN/zooo@earthlink.net> wrote in message
news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> <earle-NOSPAM-horton@msn.com> wrote:
>
> >The most common cause for backfiring on deceleration is idle mixture too
> >lean. That could be a vacuum leak with this vintage. They really do
> >have too many vacuum lines, don't they? If that is not it, then short
> >of a new or rebuilt carburetor, I don't know how you get a proper
> >idle mixture. With older models you simply back off the idle mixture
> >screw, until the engine is getting a rich enough mixture. With the smog
> >controlled models, there is
> >usually something to prevent that.
>
> Plastic caps that are easily removed with a pocket/exacto knife or the
> tip of a soldering iron (both are standard shop practices).
>
Quite. If you are going to do that, it is a good idea to record the number
of turns out for the factory setting. Just in case you later decide, that
the problem was something else.
Earle
news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> <earle-NOSPAM-horton@msn.com> wrote:
>
> >The most common cause for backfiring on deceleration is idle mixture too
> >lean. That could be a vacuum leak with this vintage. They really do
> >have too many vacuum lines, don't they? If that is not it, then short
> >of a new or rebuilt carburetor, I don't know how you get a proper
> >idle mixture. With older models you simply back off the idle mixture
> >screw, until the engine is getting a rich enough mixture. With the smog
> >controlled models, there is
> >usually something to prevent that.
>
> Plastic caps that are easily removed with a pocket/exacto knife or the
> tip of a soldering iron (both are standard shop practices).
>
Quite. If you are going to do that, it is a good idea to record the number
of turns out for the factory setting. Just in case you later decide, that
the problem was something else.
Earle
06-13-2006, 11:23 PM
#22
Guest
Posts: n/a
Re: CJ - backfiring problem help (a little long)
"Hootowl" <ELN/zooo@earthlink.net> wrote in message
news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> <earle-NOSPAM-horton@msn.com> wrote:
>
> >The most common cause for backfiring on deceleration is idle mixture too
> >lean. That could be a vacuum leak with this vintage. They really do
> >have too many vacuum lines, don't they? If that is not it, then short
> >of a new or rebuilt carburetor, I don't know how you get a proper
> >idle mixture. With older models you simply back off the idle mixture
> >screw, until the engine is getting a rich enough mixture. With the smog
> >controlled models, there is
> >usually something to prevent that.
>
> Plastic caps that are easily removed with a pocket/exacto knife or the
> tip of a soldering iron (both are standard shop practices).
>
Quite. If you are going to do that, it is a good idea to record the number
of turns out for the factory setting. Just in case you later decide, that
the problem was something else.
Earle
news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> <earle-NOSPAM-horton@msn.com> wrote:
>
> >The most common cause for backfiring on deceleration is idle mixture too
> >lean. That could be a vacuum leak with this vintage. They really do
> >have too many vacuum lines, don't they? If that is not it, then short
> >of a new or rebuilt carburetor, I don't know how you get a proper
> >idle mixture. With older models you simply back off the idle mixture
> >screw, until the engine is getting a rich enough mixture. With the smog
> >controlled models, there is
> >usually something to prevent that.
>
> Plastic caps that are easily removed with a pocket/exacto knife or the
> tip of a soldering iron (both are standard shop practices).
>
Quite. If you are going to do that, it is a good idea to record the number
of turns out for the factory setting. Just in case you later decide, that
the problem was something else.
Earle
06-14-2006, 12:30 AM
#23
Guest
Posts: n/a
Re: CJ - backfiring problem help (a little long)
Nope - no puking of oil into the air cleaner.
I'll do the various leak checks that several of you have suggested.
Not sure if there's any "plastic caps" left anywhere on the carb that
may be hiding mixture adjusting screws. Approx where on the carb will
they be located?
Lots of great advice - even from the couple old guys (says Lynn with
the full head of white hair!!)
Thanks!
Earle Horton wrote:
> "Hootowl" <ELN/zooo@earthlink.net> wrote in message
> news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> > On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> > <earle-NOSPAM-horton@msn.com> wrote:
> >
> > >The most common cause for backfiring on deceleration is idle mixture too
> > >lean. That could be a vacuum leak with this vintage. They really do
> > >have too many vacuum lines, don't they? If that is not it, then short
> > >of a new or rebuilt carburetor, I don't know how you get a proper
> > >idle mixture. With older models you simply back off the idle mixture
> > >screw, until the engine is getting a rich enough mixture. With the smog
> > >controlled models, there is
> > >usually something to prevent that.
> >
> > Plastic caps that are easily removed with a pocket/exacto knife or the
> > tip of a soldering iron (both are standard shop practices).
> >
> Quite. If you are going to do that, it is a good idea to record the number
> of turns out for the factory setting. Just in case you later decide, that
> the problem was something else.
>
> Earle
I'll do the various leak checks that several of you have suggested.
Not sure if there's any "plastic caps" left anywhere on the carb that
may be hiding mixture adjusting screws. Approx where on the carb will
they be located?
Lots of great advice - even from the couple old guys (says Lynn with
the full head of white hair!!)
Thanks!
Earle Horton wrote:
> "Hootowl" <ELN/zooo@earthlink.net> wrote in message
> news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> > On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> > <earle-NOSPAM-horton@msn.com> wrote:
> >
> > >The most common cause for backfiring on deceleration is idle mixture too
> > >lean. That could be a vacuum leak with this vintage. They really do
> > >have too many vacuum lines, don't they? If that is not it, then short
> > >of a new or rebuilt carburetor, I don't know how you get a proper
> > >idle mixture. With older models you simply back off the idle mixture
> > >screw, until the engine is getting a rich enough mixture. With the smog
> > >controlled models, there is
> > >usually something to prevent that.
> >
> > Plastic caps that are easily removed with a pocket/exacto knife or the
> > tip of a soldering iron (both are standard shop practices).
> >
> Quite. If you are going to do that, it is a good idea to record the number
> of turns out for the factory setting. Just in case you later decide, that
> the problem was something else.
>
> Earle
06-14-2006, 12:30 AM
#24
Guest
Posts: n/a
Re: CJ - backfiring problem help (a little long)
Nope - no puking of oil into the air cleaner.
I'll do the various leak checks that several of you have suggested.
Not sure if there's any "plastic caps" left anywhere on the carb that
may be hiding mixture adjusting screws. Approx where on the carb will
they be located?
Lots of great advice - even from the couple old guys (says Lynn with
the full head of white hair!!)
Thanks!
Earle Horton wrote:
> "Hootowl" <ELN/zooo@earthlink.net> wrote in message
> news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> > On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> > <earle-NOSPAM-horton@msn.com> wrote:
> >
> > >The most common cause for backfiring on deceleration is idle mixture too
> > >lean. That could be a vacuum leak with this vintage. They really do
> > >have too many vacuum lines, don't they? If that is not it, then short
> > >of a new or rebuilt carburetor, I don't know how you get a proper
> > >idle mixture. With older models you simply back off the idle mixture
> > >screw, until the engine is getting a rich enough mixture. With the smog
> > >controlled models, there is
> > >usually something to prevent that.
> >
> > Plastic caps that are easily removed with a pocket/exacto knife or the
> > tip of a soldering iron (both are standard shop practices).
> >
> Quite. If you are going to do that, it is a good idea to record the number
> of turns out for the factory setting. Just in case you later decide, that
> the problem was something else.
>
> Earle
I'll do the various leak checks that several of you have suggested.
Not sure if there's any "plastic caps" left anywhere on the carb that
may be hiding mixture adjusting screws. Approx where on the carb will
they be located?
Lots of great advice - even from the couple old guys (says Lynn with
the full head of white hair!!)
Thanks!
Earle Horton wrote:
> "Hootowl" <ELN/zooo@earthlink.net> wrote in message
> news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> > On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> > <earle-NOSPAM-horton@msn.com> wrote:
> >
> > >The most common cause for backfiring on deceleration is idle mixture too
> > >lean. That could be a vacuum leak with this vintage. They really do
> > >have too many vacuum lines, don't they? If that is not it, then short
> > >of a new or rebuilt carburetor, I don't know how you get a proper
> > >idle mixture. With older models you simply back off the idle mixture
> > >screw, until the engine is getting a rich enough mixture. With the smog
> > >controlled models, there is
> > >usually something to prevent that.
> >
> > Plastic caps that are easily removed with a pocket/exacto knife or the
> > tip of a soldering iron (both are standard shop practices).
> >
> Quite. If you are going to do that, it is a good idea to record the number
> of turns out for the factory setting. Just in case you later decide, that
> the problem was something else.
>
> Earle
06-14-2006, 12:30 AM
#25
Guest
Posts: n/a
Re: CJ - backfiring problem help (a little long)
Nope - no puking of oil into the air cleaner.
I'll do the various leak checks that several of you have suggested.
Not sure if there's any "plastic caps" left anywhere on the carb that
may be hiding mixture adjusting screws. Approx where on the carb will
they be located?
Lots of great advice - even from the couple old guys (says Lynn with
the full head of white hair!!)
Thanks!
Earle Horton wrote:
> "Hootowl" <ELN/zooo@earthlink.net> wrote in message
> news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> > On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> > <earle-NOSPAM-horton@msn.com> wrote:
> >
> > >The most common cause for backfiring on deceleration is idle mixture too
> > >lean. That could be a vacuum leak with this vintage. They really do
> > >have too many vacuum lines, don't they? If that is not it, then short
> > >of a new or rebuilt carburetor, I don't know how you get a proper
> > >idle mixture. With older models you simply back off the idle mixture
> > >screw, until the engine is getting a rich enough mixture. With the smog
> > >controlled models, there is
> > >usually something to prevent that.
> >
> > Plastic caps that are easily removed with a pocket/exacto knife or the
> > tip of a soldering iron (both are standard shop practices).
> >
> Quite. If you are going to do that, it is a good idea to record the number
> of turns out for the factory setting. Just in case you later decide, that
> the problem was something else.
>
> Earle
I'll do the various leak checks that several of you have suggested.
Not sure if there's any "plastic caps" left anywhere on the carb that
may be hiding mixture adjusting screws. Approx where on the carb will
they be located?
Lots of great advice - even from the couple old guys (says Lynn with
the full head of white hair!!)
Thanks!
Earle Horton wrote:
> "Hootowl" <ELN/zooo@earthlink.net> wrote in message
> news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> > On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> > <earle-NOSPAM-horton@msn.com> wrote:
> >
> > >The most common cause for backfiring on deceleration is idle mixture too
> > >lean. That could be a vacuum leak with this vintage. They really do
> > >have too many vacuum lines, don't they? If that is not it, then short
> > >of a new or rebuilt carburetor, I don't know how you get a proper
> > >idle mixture. With older models you simply back off the idle mixture
> > >screw, until the engine is getting a rich enough mixture. With the smog
> > >controlled models, there is
> > >usually something to prevent that.
> >
> > Plastic caps that are easily removed with a pocket/exacto knife or the
> > tip of a soldering iron (both are standard shop practices).
> >
> Quite. If you are going to do that, it is a good idea to record the number
> of turns out for the factory setting. Just in case you later decide, that
> the problem was something else.
>
> Earle
06-14-2006, 01:01 AM
#26
Guest
Posts: n/a
Re: CJ - backfiring problem help (a little long)
Try looking somewhere low, about the level of the throttle plate. You will
see a plastic cover, over an idle mixture screw. Like Hootowl says, you can
pop, cut or melt it off, depending on tools available and what works best.
In the late seventies, early eighties we used to take these off all the
time. But we found out, that if this was necessary, there was usually
another cause. Sometimes, we just didn't like the factory setting. I guess
changing it qualifies as "emissions control tampering".
Although you can tune the idle mixture "by ear" or with a tach., it is
helpful to have some kind of exhaust gas analyzer for the proceedings.
Since you probably don't have one, I would recommend, that if adjusting the
idle mixture helps, do it just enough to eliminate the backfire on
deceleration.
Earle
<lynnhowlyn@aol.com> wrote in message
news:1150259425.077582.305600@f6g2000cwb.googlegro ups.com...
> Nope - no puking of oil into the air cleaner.
> I'll do the various leak checks that several of you have suggested.
> Not sure if there's any "plastic caps" left anywhere on the carb that
> may be hiding mixture adjusting screws. Approx where on the carb will
> they be located?
>
> Lots of great advice - even from the couple old guys (says Lynn with
> the full head of white hair!!)
>
> Thanks!
>
>
> Earle Horton wrote:
> > "Hootowl" <ELN/zooo@earthlink.net> wrote in message
> > news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> > > On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> > > <earle-NOSPAM-horton@msn.com> wrote:
> > >
> > > >The most common cause for backfiring on deceleration is idle mixture
too
> > > >lean. That could be a vacuum leak with this vintage. They really do
> > > >have too many vacuum lines, don't they? If that is not it, then
short
> > > >of a new or rebuilt carburetor, I don't know how you get a proper
> > > >idle mixture. With older models you simply back off the idle mixture
> > > >screw, until the engine is getting a rich enough mixture. With the
smog
> > > >controlled models, there is
> > > >usually something to prevent that.
> > >
> > > Plastic caps that are easily removed with a pocket/exacto knife or the
> > > tip of a soldering iron (both are standard shop practices).
> > >
> > Quite. If you are going to do that, it is a good idea to record the
number
> > of turns out for the factory setting. Just in case you later decide,
that
> > the problem was something else.
> >
> > Earle
>
--
Posted via a free Usenet account from http://www.teranews.com
see a plastic cover, over an idle mixture screw. Like Hootowl says, you can
pop, cut or melt it off, depending on tools available and what works best.
In the late seventies, early eighties we used to take these off all the
time. But we found out, that if this was necessary, there was usually
another cause. Sometimes, we just didn't like the factory setting. I guess
changing it qualifies as "emissions control tampering".
Although you can tune the idle mixture "by ear" or with a tach., it is
helpful to have some kind of exhaust gas analyzer for the proceedings.
Since you probably don't have one, I would recommend, that if adjusting the
idle mixture helps, do it just enough to eliminate the backfire on
deceleration.
Earle
<lynnhowlyn@aol.com> wrote in message
news:1150259425.077582.305600@f6g2000cwb.googlegro ups.com...
> Nope - no puking of oil into the air cleaner.
> I'll do the various leak checks that several of you have suggested.
> Not sure if there's any "plastic caps" left anywhere on the carb that
> may be hiding mixture adjusting screws. Approx where on the carb will
> they be located?
>
> Lots of great advice - even from the couple old guys (says Lynn with
> the full head of white hair!!)
>
> Thanks!
>
>
> Earle Horton wrote:
> > "Hootowl" <ELN/zooo@earthlink.net> wrote in message
> > news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> > > On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> > > <earle-NOSPAM-horton@msn.com> wrote:
> > >
> > > >The most common cause for backfiring on deceleration is idle mixture
too
> > > >lean. That could be a vacuum leak with this vintage. They really do
> > > >have too many vacuum lines, don't they? If that is not it, then
short
> > > >of a new or rebuilt carburetor, I don't know how you get a proper
> > > >idle mixture. With older models you simply back off the idle mixture
> > > >screw, until the engine is getting a rich enough mixture. With the
smog
> > > >controlled models, there is
> > > >usually something to prevent that.
> > >
> > > Plastic caps that are easily removed with a pocket/exacto knife or the
> > > tip of a soldering iron (both are standard shop practices).
> > >
> > Quite. If you are going to do that, it is a good idea to record the
number
> > of turns out for the factory setting. Just in case you later decide,
that
> > the problem was something else.
> >
> > Earle
>
--
Posted via a free Usenet account from http://www.teranews.com
06-14-2006, 01:01 AM
#27
Guest
Posts: n/a
Re: CJ - backfiring problem help (a little long)
Try looking somewhere low, about the level of the throttle plate. You will
see a plastic cover, over an idle mixture screw. Like Hootowl says, you can
pop, cut or melt it off, depending on tools available and what works best.
In the late seventies, early eighties we used to take these off all the
time. But we found out, that if this was necessary, there was usually
another cause. Sometimes, we just didn't like the factory setting. I guess
changing it qualifies as "emissions control tampering".
Although you can tune the idle mixture "by ear" or with a tach., it is
helpful to have some kind of exhaust gas analyzer for the proceedings.
Since you probably don't have one, I would recommend, that if adjusting the
idle mixture helps, do it just enough to eliminate the backfire on
deceleration.
Earle
<lynnhowlyn@aol.com> wrote in message
news:1150259425.077582.305600@f6g2000cwb.googlegro ups.com...
> Nope - no puking of oil into the air cleaner.
> I'll do the various leak checks that several of you have suggested.
> Not sure if there's any "plastic caps" left anywhere on the carb that
> may be hiding mixture adjusting screws. Approx where on the carb will
> they be located?
>
> Lots of great advice - even from the couple old guys (says Lynn with
> the full head of white hair!!)
>
> Thanks!
>
>
> Earle Horton wrote:
> > "Hootowl" <ELN/zooo@earthlink.net> wrote in message
> > news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> > > On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> > > <earle-NOSPAM-horton@msn.com> wrote:
> > >
> > > >The most common cause for backfiring on deceleration is idle mixture
too
> > > >lean. That could be a vacuum leak with this vintage. They really do
> > > >have too many vacuum lines, don't they? If that is not it, then
short
> > > >of a new or rebuilt carburetor, I don't know how you get a proper
> > > >idle mixture. With older models you simply back off the idle mixture
> > > >screw, until the engine is getting a rich enough mixture. With the
smog
> > > >controlled models, there is
> > > >usually something to prevent that.
> > >
> > > Plastic caps that are easily removed with a pocket/exacto knife or the
> > > tip of a soldering iron (both are standard shop practices).
> > >
> > Quite. If you are going to do that, it is a good idea to record the
number
> > of turns out for the factory setting. Just in case you later decide,
that
> > the problem was something else.
> >
> > Earle
>
--
Posted via a free Usenet account from http://www.teranews.com
see a plastic cover, over an idle mixture screw. Like Hootowl says, you can
pop, cut or melt it off, depending on tools available and what works best.
In the late seventies, early eighties we used to take these off all the
time. But we found out, that if this was necessary, there was usually
another cause. Sometimes, we just didn't like the factory setting. I guess
changing it qualifies as "emissions control tampering".
Although you can tune the idle mixture "by ear" or with a tach., it is
helpful to have some kind of exhaust gas analyzer for the proceedings.
Since you probably don't have one, I would recommend, that if adjusting the
idle mixture helps, do it just enough to eliminate the backfire on
deceleration.
Earle
<lynnhowlyn@aol.com> wrote in message
news:1150259425.077582.305600@f6g2000cwb.googlegro ups.com...
> Nope - no puking of oil into the air cleaner.
> I'll do the various leak checks that several of you have suggested.
> Not sure if there's any "plastic caps" left anywhere on the carb that
> may be hiding mixture adjusting screws. Approx where on the carb will
> they be located?
>
> Lots of great advice - even from the couple old guys (says Lynn with
> the full head of white hair!!)
>
> Thanks!
>
>
> Earle Horton wrote:
> > "Hootowl" <ELN/zooo@earthlink.net> wrote in message
> > news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> > > On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> > > <earle-NOSPAM-horton@msn.com> wrote:
> > >
> > > >The most common cause for backfiring on deceleration is idle mixture
too
> > > >lean. That could be a vacuum leak with this vintage. They really do
> > > >have too many vacuum lines, don't they? If that is not it, then
short
> > > >of a new or rebuilt carburetor, I don't know how you get a proper
> > > >idle mixture. With older models you simply back off the idle mixture
> > > >screw, until the engine is getting a rich enough mixture. With the
smog
> > > >controlled models, there is
> > > >usually something to prevent that.
> > >
> > > Plastic caps that are easily removed with a pocket/exacto knife or the
> > > tip of a soldering iron (both are standard shop practices).
> > >
> > Quite. If you are going to do that, it is a good idea to record the
number
> > of turns out for the factory setting. Just in case you later decide,
that
> > the problem was something else.
> >
> > Earle
>
--
Posted via a free Usenet account from http://www.teranews.com
06-14-2006, 01:01 AM
#28
Guest
Posts: n/a
Re: CJ - backfiring problem help (a little long)
Try looking somewhere low, about the level of the throttle plate. You will
see a plastic cover, over an idle mixture screw. Like Hootowl says, you can
pop, cut or melt it off, depending on tools available and what works best.
In the late seventies, early eighties we used to take these off all the
time. But we found out, that if this was necessary, there was usually
another cause. Sometimes, we just didn't like the factory setting. I guess
changing it qualifies as "emissions control tampering".
Although you can tune the idle mixture "by ear" or with a tach., it is
helpful to have some kind of exhaust gas analyzer for the proceedings.
Since you probably don't have one, I would recommend, that if adjusting the
idle mixture helps, do it just enough to eliminate the backfire on
deceleration.
Earle
<lynnhowlyn@aol.com> wrote in message
news:1150259425.077582.305600@f6g2000cwb.googlegro ups.com...
> Nope - no puking of oil into the air cleaner.
> I'll do the various leak checks that several of you have suggested.
> Not sure if there's any "plastic caps" left anywhere on the carb that
> may be hiding mixture adjusting screws. Approx where on the carb will
> they be located?
>
> Lots of great advice - even from the couple old guys (says Lynn with
> the full head of white hair!!)
>
> Thanks!
>
>
> Earle Horton wrote:
> > "Hootowl" <ELN/zooo@earthlink.net> wrote in message
> > news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> > > On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> > > <earle-NOSPAM-horton@msn.com> wrote:
> > >
> > > >The most common cause for backfiring on deceleration is idle mixture
too
> > > >lean. That could be a vacuum leak with this vintage. They really do
> > > >have too many vacuum lines, don't they? If that is not it, then
short
> > > >of a new or rebuilt carburetor, I don't know how you get a proper
> > > >idle mixture. With older models you simply back off the idle mixture
> > > >screw, until the engine is getting a rich enough mixture. With the
smog
> > > >controlled models, there is
> > > >usually something to prevent that.
> > >
> > > Plastic caps that are easily removed with a pocket/exacto knife or the
> > > tip of a soldering iron (both are standard shop practices).
> > >
> > Quite. If you are going to do that, it is a good idea to record the
number
> > of turns out for the factory setting. Just in case you later decide,
that
> > the problem was something else.
> >
> > Earle
>
--
Posted via a free Usenet account from http://www.teranews.com
see a plastic cover, over an idle mixture screw. Like Hootowl says, you can
pop, cut or melt it off, depending on tools available and what works best.
In the late seventies, early eighties we used to take these off all the
time. But we found out, that if this was necessary, there was usually
another cause. Sometimes, we just didn't like the factory setting. I guess
changing it qualifies as "emissions control tampering".
Although you can tune the idle mixture "by ear" or with a tach., it is
helpful to have some kind of exhaust gas analyzer for the proceedings.
Since you probably don't have one, I would recommend, that if adjusting the
idle mixture helps, do it just enough to eliminate the backfire on
deceleration.
Earle
<lynnhowlyn@aol.com> wrote in message
news:1150259425.077582.305600@f6g2000cwb.googlegro ups.com...
> Nope - no puking of oil into the air cleaner.
> I'll do the various leak checks that several of you have suggested.
> Not sure if there's any "plastic caps" left anywhere on the carb that
> may be hiding mixture adjusting screws. Approx where on the carb will
> they be located?
>
> Lots of great advice - even from the couple old guys (says Lynn with
> the full head of white hair!!)
>
> Thanks!
>
>
> Earle Horton wrote:
> > "Hootowl" <ELN/zooo@earthlink.net> wrote in message
> > news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> > > On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> > > <earle-NOSPAM-horton@msn.com> wrote:
> > >
> > > >The most common cause for backfiring on deceleration is idle mixture
too
> > > >lean. That could be a vacuum leak with this vintage. They really do
> > > >have too many vacuum lines, don't they? If that is not it, then
short
> > > >of a new or rebuilt carburetor, I don't know how you get a proper
> > > >idle mixture. With older models you simply back off the idle mixture
> > > >screw, until the engine is getting a rich enough mixture. With the
smog
> > > >controlled models, there is
> > > >usually something to prevent that.
> > >
> > > Plastic caps that are easily removed with a pocket/exacto knife or the
> > > tip of a soldering iron (both are standard shop practices).
> > >
> > Quite. If you are going to do that, it is a good idea to record the
number
> > of turns out for the factory setting. Just in case you later decide,
that
> > the problem was something else.
> >
> > Earle
>
--
Posted via a free Usenet account from http://www.teranews.com
06-14-2006, 10:16 AM
#29
Guest
Posts: n/a
Re: CJ - backfiring problem help (a little long)
If the idle mix screws haven't been messed with recently, they are not
the issue. I would touch them only as a last resort. There are two of
them in the front of the base plate.
You are far more likely to have a loose manifold or a carboned up EGR
valve. The carb itself is known to come loose at the base plate too!
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)
"lynnhowlyn@aol.com" wrote:
>
> Nope - no puking of oil into the air cleaner.
> I'll do the various leak checks that several of you have suggested.
> Not sure if there's any "plastic caps" left anywhere on the carb that
> may be hiding mixture adjusting screws. Approx where on the carb will
> they be located?
>
> Lots of great advice - even from the couple old guys (says Lynn with
> the full head of white hair!!)
>
> Thanks!
>
> Earle Horton wrote:
> > "Hootowl" <ELN/zooo@earthlink.net> wrote in message
> > news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> > > On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> > > <earle-NOSPAM-horton@msn.com> wrote:
> > >
> > > >The most common cause for backfiring on deceleration is idle mixture too
> > > >lean. That could be a vacuum leak with this vintage. They really do
> > > >have too many vacuum lines, don't they? If that is not it, then short
> > > >of a new or rebuilt carburetor, I don't know how you get a proper
> > > >idle mixture. With older models you simply back off the idle mixture
> > > >screw, until the engine is getting a rich enough mixture. With the smog
> > > >controlled models, there is
> > > >usually something to prevent that.
> > >
> > > Plastic caps that are easily removed with a pocket/exacto knife or the
> > > tip of a soldering iron (both are standard shop practices).
> > >
> > Quite. If you are going to do that, it is a good idea to record the number
> > of turns out for the factory setting. Just in case you later decide, that
> > the problem was something else.
> >
> > Earle
the issue. I would touch them only as a last resort. There are two of
them in the front of the base plate.
You are far more likely to have a loose manifold or a carboned up EGR
valve. The carb itself is known to come loose at the base plate too!
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)
"lynnhowlyn@aol.com" wrote:
>
> Nope - no puking of oil into the air cleaner.
> I'll do the various leak checks that several of you have suggested.
> Not sure if there's any "plastic caps" left anywhere on the carb that
> may be hiding mixture adjusting screws. Approx where on the carb will
> they be located?
>
> Lots of great advice - even from the couple old guys (says Lynn with
> the full head of white hair!!)
>
> Thanks!
>
> Earle Horton wrote:
> > "Hootowl" <ELN/zooo@earthlink.net> wrote in message
> > news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> > > On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> > > <earle-NOSPAM-horton@msn.com> wrote:
> > >
> > > >The most common cause for backfiring on deceleration is idle mixture too
> > > >lean. That could be a vacuum leak with this vintage. They really do
> > > >have too many vacuum lines, don't they? If that is not it, then short
> > > >of a new or rebuilt carburetor, I don't know how you get a proper
> > > >idle mixture. With older models you simply back off the idle mixture
> > > >screw, until the engine is getting a rich enough mixture. With the smog
> > > >controlled models, there is
> > > >usually something to prevent that.
> > >
> > > Plastic caps that are easily removed with a pocket/exacto knife or the
> > > tip of a soldering iron (both are standard shop practices).
> > >
> > Quite. If you are going to do that, it is a good idea to record the number
> > of turns out for the factory setting. Just in case you later decide, that
> > the problem was something else.
> >
> > Earle
06-14-2006, 10:16 AM
#30
Guest
Posts: n/a
Re: CJ - backfiring problem help (a little long)
If the idle mix screws haven't been messed with recently, they are not
the issue. I would touch them only as a last resort. There are two of
them in the front of the base plate.
You are far more likely to have a loose manifold or a carboned up EGR
valve. The carb itself is known to come loose at the base plate too!
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)
"lynnhowlyn@aol.com" wrote:
>
> Nope - no puking of oil into the air cleaner.
> I'll do the various leak checks that several of you have suggested.
> Not sure if there's any "plastic caps" left anywhere on the carb that
> may be hiding mixture adjusting screws. Approx where on the carb will
> they be located?
>
> Lots of great advice - even from the couple old guys (says Lynn with
> the full head of white hair!!)
>
> Thanks!
>
> Earle Horton wrote:
> > "Hootowl" <ELN/zooo@earthlink.net> wrote in message
> > news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> > > On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> > > <earle-NOSPAM-horton@msn.com> wrote:
> > >
> > > >The most common cause for backfiring on deceleration is idle mixture too
> > > >lean. That could be a vacuum leak with this vintage. They really do
> > > >have too many vacuum lines, don't they? If that is not it, then short
> > > >of a new or rebuilt carburetor, I don't know how you get a proper
> > > >idle mixture. With older models you simply back off the idle mixture
> > > >screw, until the engine is getting a rich enough mixture. With the smog
> > > >controlled models, there is
> > > >usually something to prevent that.
> > >
> > > Plastic caps that are easily removed with a pocket/exacto knife or the
> > > tip of a soldering iron (both are standard shop practices).
> > >
> > Quite. If you are going to do that, it is a good idea to record the number
> > of turns out for the factory setting. Just in case you later decide, that
> > the problem was something else.
> >
> > Earle
the issue. I would touch them only as a last resort. There are two of
them in the front of the base plate.
You are far more likely to have a loose manifold or a carboned up EGR
valve. The carb itself is known to come loose at the base plate too!
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)
"lynnhowlyn@aol.com" wrote:
>
> Nope - no puking of oil into the air cleaner.
> I'll do the various leak checks that several of you have suggested.
> Not sure if there's any "plastic caps" left anywhere on the carb that
> may be hiding mixture adjusting screws. Approx where on the carb will
> they be located?
>
> Lots of great advice - even from the couple old guys (says Lynn with
> the full head of white hair!!)
>
> Thanks!
>
> Earle Horton wrote:
> > "Hootowl" <ELN/zooo@earthlink.net> wrote in message
> > news:21vu82l7jci6u3bos7mp5o69icghn1vc5l@4ax.com...
> > > On Tue, 13 Jun 2006 08:42:40 -0600, "Earle Horton"
> > > <earle-NOSPAM-horton@msn.com> wrote:
> > >
> > > >The most common cause for backfiring on deceleration is idle mixture too
> > > >lean. That could be a vacuum leak with this vintage. They really do
> > > >have too many vacuum lines, don't they? If that is not it, then short
> > > >of a new or rebuilt carburetor, I don't know how you get a proper
> > > >idle mixture. With older models you simply back off the idle mixture
> > > >screw, until the engine is getting a rich enough mixture. With the smog
> > > >controlled models, there is
> > > >usually something to prevent that.
> > >
> > > Plastic caps that are easily removed with a pocket/exacto knife or the
> > > tip of a soldering iron (both are standard shop practices).
> > >
> > Quite. If you are going to do that, it is a good idea to record the number
> > of turns out for the factory setting. Just in case you later decide, that
> > the problem was something else.
> >
> > Earle