Weber jets

[Anonymous]

Can someone direct me to the post discussing the various Holley/Weber jets? I haven't looked at mine yet but I pulled the spark plugs this morning and they look a little clean. Maybe too lean of a fuel/air mixture.



-Chris

 

[Anonymous]

Chris,

Do you know which jets you have in there now? You basically have 2 simple options (there are others) :

1) increase the size of your main fuel jets (these are the ones in the bowel)

2) decrease the size of your main air jets (these are the ones above the emulsion tubes. You can see them looking down the choke)

The air jets typically affect the top end mixture. If you go to a larger main fuel with good results, and notice the top end is a little rich (soft in power) you can use a larger air jet to correct this.

I've setup a couple of 32/36 carbs on 200s and a 160-175 main fuel jet with a 175-185 main air jet will get you close, but each engine setup will vary. Most of the Holley/Webers I've seen have fairly small main fuel jets (120 - 150)

 

[Anonymous]

Thanks John.

First, do you have a diagram of the jet locations. The only ones I saw tonight where visible without taking anything apart. These are stamped 185 and the other 140.



-Chris

 

[Anonymous]

I do... but no scanner. Those jets you can see are the main air jets.

Remove the 6 screws on top of the carb and the clip for the choke flap - pull the top off the carb and you will find the 2 main fuel jets.

 

[Anonymous]

Okay, opened the carburetor this morning and here are the jet sizes:

Main Jets: 180 , 135
Air Jets: 185 , 140
Idle Jet: 60

I think I need to change the idle jet to something larger. I say this because I have to almost back out the fuel/air fixture screw in order for it to idle well. That worries me. I followed RedLine Weber carburetors instruction on setting up the carburetor and all went well expect for the fuel/air fixture screw setting. I think I had to back it out about 4 turns.

Ideas, suggestions.

I think someone else said they had to go with a 65 idle jet as well. What about my other jets? My engine is stock. '68 block and '77 head. approx. 8.5 : 1 compression ratio.



-Chris

P.S. I also noticed that whenever the secondary kicks in, the engine bogs for a second or two and then recovers.

 

[trashline]

i think your air jets are a bit to big bc you said you have bogging, id reduce them but not alot at all. and id agree with you on the idle jet. your attempting to richen the idle by moving the screw all the way out .now you can put a bigger jet in and and do the same thing. just use a vacumm gauge to find the best point

 

[Anonymous]

Well, I just got off the phone with Tom (nice guy) and he recommended a 65 primary idle jet and 60 for the secondary idle jet (something I didn't even think about).

He is sending me the jets today - no charge!

I'll keep you all posted of the results.



-Chris

 

[trashline]

did he say anything about the air and fuel jets? did he say they were ok? and just to up the idle jets?

 

[Anonymous]

He said try the idle jets he is sending first (there are two - something I didn't know). Then, if I still have the bogging when the secondary kicks in, try a smaller primary main jet and a smaller primary air jet. He said they sound a little big when working inconjunction with the secondarys. The ideal setup for a stock 200 would be something like:

Main: 170 , 140
Air: 150 , 120
Idle: 65 , 60

We'll see.



-Chris

 

[Anonymous]

Chris,

Your engine hessitates when you open the secondary because there is no extra accelerator pump action. Installing a #70 secondary idle jet has helped me with that before.

 

[Anonymous]

Thanks John.

After looking at my idel jets again, I noticed the primary and secondary are not what I had originally posted (hard to read). I took out my magnifying glass and found that they are 60 and 55, respectively.

I should be getting the new jets in tomorrow. As soon as I change them out I'll report my findings, again.

Thanks again guys for all your help on this subject! Seriouslly!

BIG BEAR HUNG!


-Chris

 

[Anonymous]

HUG, I mean. :roll:



-Chris

 

[cfmustang]

This may be a dumb question, but do you have to remove the weber from the log to replace the jets? When you do change jets, do you have to completely dismantle the carb? Does that require gaskets?

I am probably headed in this direction myself, and I have been wondering about this.

 

[trashline]

one set of jets are obtainable from the outside. just be careful ad you should be ok inspect for any damage and ifso replace. a carb rebuild kit is a good thing to have sitting around too bc you never know when playing with it you could lose or break something

 

[Anonymous]

cfmustang, all jets are accessable without removing the carburetor. The only gasket that you may (notice I said may) have to change out would be the one that seals the top plate to the rest of the carburetor (similiar to the Motocraft and Holley carburetors). Mine was in excellent shape. No leaks after I swapped the jets.

Speaking of swap. I got the replacement jets today in the mail and installed them this evening. Awesome. BIG improvement of the stock settings.

Here is my final jet numbers (yes, there are six jets):

Primary Main - 180
Secondary Main - 135
Primary Air - 185
Secondary Air - 140
Primary Idle - 70
Secondary Idle - 60

So, after the idle jet changes it really smoothed out the engine. So far no more bogging whenever the secondary kicks in.

Am I happy - oh ya.

Now, on to my custom air cleaner. Got the sheetmetal today and angles today. I'll post some pictures of my progress hopefully tomorrow.

Folks, I can't express enough how great this upgrade has been. Considering the simplicity and cost factor involved, I just don't see why I waited so long in performing this upgrade.

After the air cleaner - dual Webers!



-Chris

 

[Anonymous]

Chris, glad it worked out for you. Now your next project should be fitting that Weber straight to the intake manifold.