help with triple webers!!

J

JOHN G

Well-known member
Thanx to all that have put up with me to this point-your info has gotten me runnin better, but I'm still not quite there. Problem-the car idles pretty well, but under light accel, it stumbles until I open up the other two carbs and build some rpms. It then comes to life, but still not what I'm led to believe it can do. I'm getting pinging in the mid rpm range which I'm gonna blame on the vac advance. I'm runnin the stock jets and some have told me to jet up the main carb. The plugs on the middle two runners came out a little sooty though which would indicate a rich condition. I do however hear the middle carb spitting at idle which usually means a lean condition. Anybody out there experience this/explain this? What kind of vac readings should I get from the port and manifold vac lines with the setup I have? I'm getting about 13 lbs. from the port which seems a little low, but the guage is steady so I don't think I have a leak- the timing mark stays very steady too which backs this up. Somebody please make my Christmas!!!
Thanx again!
 
John,

Sounds like you have too small of a main jet in the primary. What is your current jetting?

Are these ICH or ICT carbs? I would start with a 170 gas, 195 air corrector, and a 60 idle. Anything near those numbers? What emulsion tube did they come with?

As for the plug reading - it´s sounds like a rich idle. That explains the stumble at idle and your suity plugs in the center. The plugs are only going to tell you the mixture condition at the point where the engine was shut off... while idling?
 
The carbs are the ones that clifford is selling-can't remember which one. They insist that they run-em out of the box with the factory 40 jet-I can't see how! I don't however know what the other numbers are as I installed them right out of the box. The end plugcome out with a nice brownish tint so I know I'm in the range with the end carbs. If it helps, the carbs are manual choke, 34 cm, with idle cut-off solenoids and I know that they where the replacement bmw carbs. If this doesn't help, I'll dig up one of the boxes in the morning. Like I thought, it sounds like the main is lean with the spitting and the lack-luster performance off the line. If I come around a corner with some steam and nail it, it'll tear the tires pretty well. Other than that, it definteley isn't right-close though I suspect. Please excuse any spelling errors as I have a two year old in my lap as I type!
 
One other thing I forgot, the idle is very hard to adjust-specifically, I can't seem to get it low enough-I've got the screw all the way out and it still idles at aroud 1100 in neutral. The other idle solenoids are not energized and I put springs on the other carb linkages to hold them shut at idle.
 
John,

First, stop listening to Clifford so much. I bought a Weber from them 5 years ago and asked for the jets sizes. I opened the carb later to find that the jetting specs they gave me where nowhere close to what was actually in the carb... thanks Clifford.

Now, this is simple. Take the top off of the center carb and find the sizes of the jets:

The air corrector will be right up on top. It sits on top of the emulsion tube. The main jet will either be in the bottom of the fuel bowel or directly under the emulsion tube. The idle jet should be accessable from the outer body of the carb on the side - about half way up the body of the carb.

I suggest unhooking the linkage to the outer carbs to isolate the center carb. Get it tuned, and then move forward.
 
Oh boy have i figured out about clifford-we all learn by our mistakes! I bought my offy through summit auto racing (40 minutes from house) for a
$100 less than cliffys(see, I'm learning already!)This was my first venture into inline building and I wasn't aware of all the resources. I will pop the top on that carb today or tommorrow morning and report back with my findings. The other item that I was told no by the Big "C" was the D II setup-seems like many others are using it with great success! By the way, I don't mean to bash on them, I just think there are other ways.
 
Thanx, I agree those years rock! I have pics and as soon as I can get them posted, I will do so. How do I get a pic to show up automatically with each post?
 
I really, really like the 66/67 Fairlanes and Comets. Here are a couple of my 67 Comet 2dr sedan:

comet3.jpg


comet5.jpg


I wanted a hardtop, but this one basically fell in my lap and I couldn't turn it down. 8) No six for this one either, rather, a stout FE will grace the engine bay. Visit my webpage for a few more pics.
 
Very cool!!! I thought I had the only one in existence at this point! I'm still working on getting those pics loaded-I'd rather get the darn thing runnin right first, but since it is cold.... My pics should be at Comet Central.com soon.
 
From my short stint with multi carbs:

1) Check your mechanical linkage...maybe they are coming in too soon. That's part of the problem with mechanical linkages is that you may be flooding the engine at low RPMs. I found with the Offy set up, you really had to ease the gas pedal if you were in gear (at least for manual tranny) so you wouldn't flood out the engine. Remember, when those outers start to open, you get a squirt from the accelerator pump. Try to adjust that so it squirts less.

2) To get the idle down, you are going to have to run the center carb a little rich at idle. The only way I got my idle below 800 RPM with this set up was to almost completely close the outer carbs idle circuits. The only problem is that this ends up creating a small vacuum leak around the butterfly and by running the center carb rich, I was able to get better idle quality. When I say almost closed, I mean...close, and back open maybe 1/16 to 1/8 of a turn on the idle mix.

3) Make sure your outer carbs accelerator pumps are set to the same setting.

4) Check your timing, and double check it.

5) 13# is a little low with a stock or even mild cam. Really check for a vacuum leak around the outer carbs. Get some carb spray and spray both the bases and the adaptor on the base as well. I got a vacuum leak there after a backfire.

Good luck.

Slade
 
What gear you running? I've got 2:80 or 3:00 I was thinking about 3:56, but I would like to maintain 65 on the freeway. I'd go steeper yet as long as I can hit freeway cruise speed. I'm gonna check the manifold vac and see what it reads-I'm using my mityvac to guage with & I'm starting to doubt it's accuracy. Everyone is telling me to rejet and I can tell I need to.
 
so is 3:56 too high for my application? I'll get a better guage after work-I don't suspect a vac leak though as the guage I have now is steady and the timing mark is very steady.
 
here are some pics of my 67 fairlane with the 200 and a 3sp 3.03 tranny column shifter...enjoy!
 
3.56 with a 3.03 3-speed? You'll have hella acceleration, but above 65-70MPH you'll be running above 3000RPM depending on your tires.

Slade
 
You must log in or register to reply here.

Similar threads

R
All Small Six 1964 F100 223 tuning issues
2
Replies
35
Views
2K
philford
philford
S
All Small Six My 250 journey is over... :(
Replies
16
Views
3K
chad
chad
awasson
All Small Six Weber 38/38 DGES jets, emulsion tubes and settings
Replies
9
Views
1K
awasson
awasson
funkaholik
All Small Six CC'ing Combustion Chambers
Replies
5
Views
1K
78_200_C4
7
T
Build Thread Turbo 250 Mod Log 2.0
2
Replies
31
Views
6K
Jmustang_65
J
Back
Top