MIKUNI CARB AJUSTMENT
Wayne Taylor
carb from a 2.6 Mitsubishi? Can adjust the curb idle (when warm) but
can't seem to locate the choke idle speed adjustment. The shop manual
doesn't show it.
The engine currently races far too many rpms when first startup and cold.
Thanks,
Wayne.
Terry P Gleason
There is a hard to reach cold adjustment screw but the large spring
choke mechanism was overriding and preventing any effective
adjustment. I eventually pushed open the choke by prying against the
large spring and jamming a large bolt in the space to hold it open.
This worked fine thru the summer but with the colder weather it would
stall until warm. I then took out the bolt and found I could make a
cold idle adjustment. Don't know why but I suspect something was
preventing the spring from turning freely. I also removed a cover
plate facing the radiator to better see and access the adj screw(s).
In article <4cduem$u...@sanjuan.islandnet.com>,
--
Terry P. Gleason
Speech Systems and Technology Group
MIT Lincoln Laboratory
e-mail: t...@sst.ll.mit.edu
Doug Russell
>Anyone really familiar with the choke idle speed adjustment on the Mikuni
>carb from a 2.6 Mitsubishi? Can adjust the curb idle (when warm) but
>can't seem to locate the choke idle speed adjustment. The shop manual
>doesn't show it.
>The engine currently races far too many rpms when first startup and cold.
Eeew... I really dislike those carbs... My girlfriend has an 83 Challenger
with the 2.6, which we recently rebuilt. I've never liked that carb so we
replaced it with a Rochester 2GC... Anyways, on to your question...
Yes, there is an adjustment screw. It is kinda hidden, but it is basically
just below the dashpot adjusting screw (the one to the right of the curb idle
speed screw).... Down underneath the little lever off the dashpot... if your
carb has the dashpot....
Also, another thing to check / another way to adjust it if it's WAY out of
whack... The two pieces of the hot water choke may not be lined up correctly.
Take a look at that little curved, toothed, arm by the choke, and the little
plastic wheel. (As the choke opens/closes the wheel moves along the bar... or
the other way around, however you want to look at it.) anyway, THEORETICALLY
the little notch and the dot should be alligned when the choke is in the
middle. (You should be able to tell whet I'm talking about when you look at
it... They each have a locating mark on them that are supposed to be aligned
when you assemble the thing, so you know the right tooth is in the right
place...) I always had to have the one on the Challenger one notch higher in
choke/speed to make it adjust properly. In your case, move it one down from
the current position.
I hope this helps... It's kinda tricky for me to tell exactly where something
is/was, because the carb is disassembled, in a salad bowl, here on my bench...
I figure it is what it deserves for being such a wacky carb... :-) Someday
I'll clean it up and re-assemble it in case someone I know ever needs one.
We're sticking with the Rochester... It added about 10 HP just by switching
carbs... not to mension easier starting, a choke system that is reliable, and
about 100 times less parts....
Later...... <Doug>
Tom Kennelly
the Mikuni and would like to replace it someday. Currently I have taken
the choke plate out of the carb, and since I live in Florida it hasn't
been much of a problem.
Doug Russell
It isn't the "right" carb.... It doesn't even bolt directly onto the
manifold. I had to fabricate an adaptor plate out of a piece of aluminum,
some carb studs, screws, etc. The adaptor allows me to bolt on any standard
4-bolt 2bbl carb (ie a Holley, Rochester 2G series, Carter, etc. etc.) The
one that I chose was a Rochester 2GC from a '76 sunbird (2.8l V6), which has a
stock flow rating of 280 CFM, which is right on the money for the 2.6l.
It is a lot nicer than the Mikuni, and can easily be calibrated with readily
available jets, etc.
Of course, you can't do this when you are limited by emission requirements.
The Canadian version of the car doesn't have a catalytic convertor, so the
air:fuel ratio isn't critical, and Alberta has no emission laws, no tests to
pass. Although, with the carb adjusted correctly (as it is) it is probably
generating less polution than the slightly malfunctioning Mikuni.
I'm working on a section on my web page on the restore of the Challenger, but
it's not done yet. I still need to scan some more pictures... but it should
be up in a couple of weeks at http://www.ucalgary.ca/~dwrussel. There will be
a section on the Mikuni carb, the swap, and the Rochester.
Later...... <Doug>