I have a 1985 Chev Caprice Wagon with a Quadrajet (17085990)
Non-computer/electric choke and have an intermittent flooding problem. The
car will flood so bad that it will stall out with fuel dripping out from
the somehere near where the choke attaches. Following the stall it will
require WOT to start. Other times it will run just fine, quite well in fact.
Just this afternoon I barely could keep the car running to get back to work.
I parked the car (level) until I left for home about three hours later and
the car started and ran just fine all the way home (about 30 minutes in
I had removed the carb, cleaned out bowl, installed new needle valve/seat,
filter etc. but problem still persists.
I will take the carb off again this weekend but am not sure what I should be
looking for but I suspect the needle valve is somehow at fault.
I have the original mechanical fuel pump but it was replaced about 50K miles
Any advice would be appreciated.
Whew! Kinda threw me off there for a minute. I didn't now that the
1895 Chevy had a Q-Jet LOL. One problem with the older Q-Jets was the
plugs in the secondary wells. They would leak after the carb heated up
and fuel would leak down into the manifold through a weep hole in the
base. This problem usually caused it to flood after it sat for a short
period of time. The fix for this was to drill out the plugs and replace
them with O-ringed plugs - OR - install a rubber plug in the void that
prevented the wells from leaking.
But, you said that it was leaking around the choke so this may not be
your problem. Since you have replaced the needle and seat, did you
re-check the float level? As I remembe it, the only passageways around
the choke carried vacuum and heated air.
I second the suggestion about the float level. Likely, it is set too
high, is sinking (very possible with older soldered brass type, newer
black closed-cell plastic less likely). Perhaps the needle is
sticking; if the fuel filter has been allowed to clog, the incoming fuel
pressure will push the filter back on the bypass spring (which *is*
present, correct?) and unfiltered fuel will enter the carb. This
situation could cause repititive needle sticking, particularly with an
older vehicle, as quantities of detritus may have accumulated in the fuel
tank over the years. A less likely possibility would be burrs or damage
on the float arm or pivot pin, causing the float to bind and hold the
needle up. Omission of the black plastic filler in the bowl can cause
fuel sloshing during vehicle maneuvers, but I would guess it would
require some seriously aggressive driving, coupled with a high float, to
slosh enough fuel out the vents and into the venturii to flood the motor
out. Leaving out the filler usually causes a lean out when slosh
uncovers the jets.
Obviously, the choke assembly should be checked over to insure that the
butterfly is opening fully as the engine reaches operating temperature.
Some Q-Jets use a pull-over choke enrichment system (I do not know if your carb
does or not) that can be identified by two small calibrated holes in the
throat of the choke tower, just below the choke butterfly's closed rear
edge. If the choke is not fully opening, these orifii may discharge
fuel, greatly amplifying the over-rich condition of a malfunctioning
A full cleaning/rebuild may not be a bad idea at this point, as once a
seasoned air horn gasket is pulled up, it's pretty much trash.
On a somewhat related note, the carb number given does not compute; the
second to last digit indicates the division, and '9' was used only on Q-Jets
manufactured for Ford on the 428CJ engine. (FoMoCo/Holley couldn't build
a carb that would pass smog reqs.) If you try to find that number on an
adjustment specs table in a rebuild kit, it won't be there. The division
number should be 0,1 or 2 for a Chev. Furthermore, a 1708 series
passenger carb is an E4M, or computer-controlled carb--you are positive
your carb does not have TPS and MCS connectors (non-ECM)?
On Thu, 23 Oct 2003 19:05:07 -0600, Lloyd Cimprich wrote:
Thanks all for the feedback, the Carb # is correct as stamped, in fact I
have three of these cars all with identical carb and #. Two are 85 Caprice
wagons and one is an 83 Caprice sedan and I have not been able to find a
spare carb of same #. Can anyone suggest an equivalent?
The car ran perfect, smooth and even power, all day today!! I think I will
install a clear in-line filter as I suspect something must be getting to the
float needle. Just in case I will pull the carb and re-check all assembly
A Q-jet overhaul can be performed, even by a novice, on a Saturday at a
cost of $30. An AFB (called performer when sold by Edel) will cost at least
$250, plus rods/jets as necessary
to dial it into the car, and require at least as much time to tune as the
Q-Jet overhaul, which is obviously already calibrated to the engine.
Admittedly, I am not much of a fan of the E4M (computer) QuadraJets on
non-stock engines, but even a
1705 series "emissions" mechanical QJet will, properly set up, beat the socks
off an AFB any day of the week. The correct QJet, with a little tweaking, can
support a 9 second drag car.
I am personally very interested in learning more about the three carbs on
the Caprices; I am not insinuating that Mr. Cimprich's information about
the stamped numbers is wrong, but I am rather intrigued that three carbs
(including one of the incorrect year for the vehicle as per stamping) of
similar application all appear to be improperly stamped. (assuming, of
course, that they are the original carbs.)
On the subject of replacement carbs, any QJ from a similar displacement
and power rating engine application can be made to work sufficiently
here. The only catch is that an E4M (computer) carb must be used with an
ECM and 7-pin HEI module; an M4M (non-computer) carb must be used with a
4-pin HEI module. In short, if there is a weatherpack connector attached
to the distributor, use an E4M.
Cheers from a QJ fanatic,
On Fri, 24 Oct 2003 19:26:56 -0600, Eightupman wrote:
Yes....I agree the kit can be bought for about $30, and rebuilt yourself,
but I was speaking of a factory remanufacture...not a bench rebuild. I also
found a factory remanufactured Edelbrock for about $189 (consumer price).
Ultimately he wants the car fixed. And truthfully I would spend the $30
first and try to rebuild it myself...but most would not want to be bothered.
And it would be an excuse to spend a little extra mad money on a toy...
I've rebuilt a few pre-emission Q-Jets and they really aren't that
difficult. The secret of doing a home-rebuild is to get a good manual
(in addition to the instructions that come with the kit) and take your
time doing the job. The performance of the Q-jet depends on how well
you set the carb up on the bench. I got my manual from Helms and while
it wasn't a very lengthy manual, it covered the subject well. Just
remember to keep all extraneous dirt out of the carb or you'll be
wasting your time.
I was not able to obtain the correct float in time to install but I did
install a filter in the rubber fuel line just before the pump. When I parked
the car to install the filter it was running great but started to flood
again when I restarted and had to pump throttle a couple dozen times to
clear it up.
It ran just great until today when I moved the filter around to try and see
what it trapped. Once again it flooded just after startup and took a little
while to clear up.
I am beginning to think the rubber fuel line to pump is breaking up.
Now that I have the new float I remove carb, open it up, inspect and clean
and install new float. I think I saw a suggestion that the needle should
hang from the float in a particular way but do no remember which way.
Any additional thoughts from the group would be appreciated.
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